System of sharing objects having a plurality of contents

ABSTRACT

In order to use video contents created according to DVD video in DVD audio, audio and video sub-directories are located under a root directory. The video sub-directory includes video contents and their management information. The audio sub-directory includes audio contents and their management information. The video management information can only access the video contents. However, the audio management information can access not only the audio contents but also the video contents.

This application is a division of application Ser. No. 09/380,067 filedAug. 25, 1999 now U.S. Pat. No. 6,748,160, which was filed as PCTapplication No. PCT/JP98/05908 filed on Dec. 25, 1988.

TECHNICAL FIELD

The present invention relates to a system for sharing objects of aplurality of contents (various video contents, various audio contents,and the like).

BACKGROUND ART

Also, the present invention relates to an information medium havingmanagement data for sharing objects of a plurality of contents, anapparatus for playing back information recorded on the medium, a methodof recording information containing the management data on the medium,and a method of playing back information from the medium on the basis ofthe management data.

As optical discs that can record video (moving picture) data with highquality and at high density, and can record various kinds of informationsuch as multiangle video data, sub-picture data, multilingual audiodata, multichannel audio data, and the like, DVD video discs have beendeveloped, and are beginning to be put into the market (DVD is anabbreviation for a digital versatile disc).

The DVD video disc standards can support compressed multichannel audio(AC-3, MPEG, and the like) and non-compressed linear PCM (from asampling rate of 48 kHz/16 quantization bits to a sampling rate of 96kHz/24 quantization bits). Linear PCM of DVD video has high-soundquality specifications with high sampling rate and high quantizationbits superior to conventional music CDs (a sampling rate of 44.1 kHz/16quantization bits). Especially, linear PCM having a sampling rate of 96kHz/20 to 24 quantization bits qualifies for the next generation digitalaudio discs (so-called super CDs or super audio discs).

However, DVD video specifications give priority to video over audio, andaudio priority specifications superior to audio specifications of DVDvideo in terms of not only the sampling frequency and the number ofquantization bits but also the number of recordable channels, recordabletime, and the like, are yet to come.

To meet such demand, DVD audio specifications are being explored(however, the DVD audio specifications are not yet a prior art). The DVDaudio specifications can support up to linear PCM having a sampling rateof 192 kHz and 24 quantization bits as well as linear PCM having asampling rate of 48 kHz to 96 kHz and 16 to 24 quantization bits. In thefuture version up of DVD audio specifications, higher-sound qualityspecifications may be introduced.

DVD audio can cope with such future scale-up since it can commonly usesome specifications of DVD video capable of large-amount recording thatincludes even digital Hi-Vision video as a target.

Also, DVD audio can take future technical, market, and economicadvantages that will become available along with the improvement of DVDvideo.

For example, when a large-amount DVD disc which will be available in thefuture in DVD video is used in DVD audio, the sampling frequency, thenumber of quantization bits, the number of recording channels, and thelike used in recording can be increased considerably if the recordingtime remains the same. The technique of a DVD video recorder which willbe put into the market in the near future and uses a DVD-RAM (orrewritable DVD-RW or write-once DVD-R) can be used in a DVD audiorecorder that will become available soon.

Furthermore, if the market scale expands as DVD video prevails, media(DVD-ROM discs, DVD-RAM/DVD-RW discs, DVD-R discs, and the like),components (disc drive, optical pickup, various ICs, and the like),various control programs, and the like are standardized, and a costreduction of DVD audio products having many features and high soundquality is promoted. With the spread of DVD audio, DVD video can alsotake future technical, market, and economical advantages that willbecome available along with the improvement of DVD audio.

As a management method for controlling playback of video (movingpicture) or audio (music or the like) contents, it is a common practiceto manage playback of contents produced according to their purposes. Bycontrast, with recent diversification of users' requirements, video andmusic have vague boundary, and requirements for partly using thecontents that can be independently played back as video in music or forcommonly using contents by allowing video created for music to be playedback as video alone are increasing among producers of these contents(contents providers).

The DVD audio specifications according to the present invention can meetsuch requirements of the contents providers. More specifically, the DVDaudio specifications normally give priority to audio over video, but itis possible to build a system compatible with both DVD video and DVDaudio. That is, the DVD audio specifications can provide an audio onlydisc (A disc) including DVD audio contents alone, and an audio+videodisc (AV disc) including both audio and video contents. In such case,upon playing back the audio contents of an AV disc, its video contentscan also be accessed.

In the DVD audio specifications according to the present invention, notonly video picture data as subsets of the DVD video specifications, butalso high-resolution still picture data, text information, and menu data(visual menu data that can be freely designed by the contents provider)can be added to audio data with high-sound quality specifications.

DISCLOSURE OF INVENTION

It is the first object of the present invention to provide a digitalinformation medium which can access not only DVD audio information butalso part (e.g., some video data) of DVD video information in theaforementioned DVD audio specifications.

It is the second object of the present invention to provide an apparatusfor playing back information from the digital information medium.

It is the third object of the present invention to provide a method ofrecording information on the digital information medium.

It is the fourth object of the present invention to provide a method ofplaying back information from the digital information medium.

In order to achieve the first object, in a digital information mediumaccording to the present invention, first and second contents (ATS, VTS)for different purposes are recorded on a plurality of independent areas(DVD audio zone, DVD video zone). The first and second contents (ATS,VTS) respectively have first and second management blocks (AMG, VMG) tomanage playback of their contents. The first management block (AMG) hasfirst information (AMGI) for managing accesses to both the firstcontents (ATS) and second contents (VTS).

In the medium of the first object, the second management block (VMG) mayhave second information (VMGI) for managing accesses to the secondcontents (VTS).

In the medium of the first object, the first management block (AMG) hasphysically or logically smaller address numbers than the secondmanagement block (VMG) or the second contents (VTS).

In the medium of the first object, the first contents (ATS#1) mayinclude information (link information) for accessing the second contents(VTS).

In the medium of the first object, files of recorded information may bemanaged by a hierarchical file structure including the followingsub-directories and root directory. That is, recorded information filescan be managed by: a first sub-directory (ATS directory) including adata file (ATS_(—)01_(—)0.AOB) for storing the first contents (ATS) anda data file (AUDIO_TS.IFO) for storing the first information (AMGI); asecond sub-directory (VTS directory) including a data file(VTS_(—)01_(—)1.VOB) for storing the second contents (VTS) and a datafile (VIDEO_TS.IFO) for storing the second information (VMGI); and aroot directory containing the first sub-directory (ATS directory) andthe second sub-directory (VTS directory).

In the medium of the first object, the data file (ATS_(—)01_(—)0.AOB) inthe first directory (ATS directory) may be formed by objects (AOTT)which contain at least audio data but do not contain video data); andthe data file (VTS_(—)01_(—)1.VOB) in the second sub-directory (VTSdirectory) may be formed by objects (VTS) which contain video data.

In the medium of the first object, the first information (AMGI) maycontain first search information (ATT_SRP for AOTT) for accessing theobjects (AOTT) which contain audio data but do not contain any videodata, and second search information (ATT_SRP for AVTT) for accessing theobjects (VTS) containing video data.

In the medium of the first object, the second information (VMGI) maycontain search information (ATT_SRP for AVTT) for accessing only theobjects (VTS) containing video data.

In order to achieve the first object, an optical disc according to thepresent invention has a lead-in area (27) at the center, and a volumespace (28) and lead-out area (26) in turn around the lead-in area; thevolume space (28) contains an audio zone (71) and then a video zone(72); the audio zone (71) contains audio management information (AMG)and audio contents (ATS); and the video zone (72) contains videomanagement information (VMG) and video contents (VTS). In this opticaldisc, the audio contents (ATS) and video contents (VTS) can contain datacells (VTS_C#2 and the like) which are commonly managed by the audiomanagement information (AMG).

In the optical disc of the first object, the video contents (VTS) cancontain data cells (VTS_C#2 and the like) managed by the videomanagement information (VMG), and each of the data cells (VTS_C#2 andthe like) managed by the audio management information (AMG) or videomanagement information (VMG) can be formed by a set of data packs eachhaving a predetermined size (2,048 bytes).

Furthermore, in order to achieve the first object, another optical discaccording to the present invention has a lead-in area (27) at thecenter, and a volume space (28) and lead-out area (26) in turn aroundthe lead-in area; the volume space (28) contains an audio zone (71) andthen a video zone (72); the audio zone (71) contains audio managementinformation (AMG) and audio contents (ATS); and the video zone (72)contains video management information (VMG) and video contents (VTS). Inthis optical disc, the audio contents (ATS) contain one or more datacells (audio cell, picture cell, silent cell) managed by the audiomanagement information (AMG), and each data cell (audio cell, picturecell, silent cell) is formed by a set of one or more data packs (A_PCK,SPCT_PCK, and the like) each having a predetermined size (2,048 bytes).

In the other optical disc of the first object, at least one data cell(audio cell) can be formed by packs (A_PCK) of audio information.

In the other optical disc of the first object, at least one data cell(silent cell) can be formed by packs (A_PCK) of audio informationconsisting-of silent information.

In the other optical disc of the first object, the audio contents (ATS)may contain audio title set information (ATSI) for managing itscontents, the audio title set information (ATSI) may contain programchain information (ATS_PGCI in ATS_PGCIT) for managing one or moreprograms (PG#) that form the audio contents (ATS), and the program chaininformation (ATS_PGCI) may contain information (ATS_C_SA, ATS_C_EA inFIG. 28) indicating the recorded positions of the data cells (audiocell, picture cell, silent cell).

In the other optical disc of the first object, the audio contents (ATS)can contain an audio title set (ATT or AVTT) which includes informationpertaining to both audio and video, and an audio only title set (AOTT)which includes information pertaining to only audio.

In the other optical disc of the first object, the audio managementinformation (AMG) can contain information (ATT_SRPT in FIG. 20, thelocation of which is specified by ATT_SRPT_SA in AMGI_MAT in FIG. 18) ofa search pointer (ATT_SRP) for accessing the audio title set (ATT).

In the other optical disc of the first object, the audio managementinformation (AMG) can contain information (AOTT_SRPT in FIG. 20, thelocation of which is specified by AOTT_SRPT_SA in AMGI_MAT in FIG. 18)of a search pointer (AOTT_SRP) for accessing the audio only title set(AOTT).

In the other optical disc of the first object, the audio contents (ATS)can contain audio data (AOTT_AOB) digitally converted by a predeterminedsampling frequency (e.g., 192 kHz) selected from a plurality ofdifferent sampling frequencies (48 kHz, 96 kHz, 192 kHz, and the like)and a predetermined number of quantization bits (e.g., 20 bits) selectedfrom a plurality of different numbers of quantization bits (16 bits, 20bits, 24 bits, and the like), and attribute information (AOTT_AOB_ATR inFIG. 25 included in ATSI in FIG. 24) indicating the predeterminedsampling frequency (e.g., 192 kHz) and the predetermined number ofquantization bits (e.g., 20 bits) used for this audio data (AOTT_AOB).

In order to achieve the second object, a playback apparatus according tothe present invention has an audio management block (AMG) for managingaudio contents (ATS) and their playback, and a video management block(VMG) for managing video contents (VTS) and their playback, the audiomanagement block (AMG) plays back the audio contents (ATS) or videocontents (VTS) from a digital information medium (AV disc 10) containingaudio management information (AMGI) for managing accesses to the audiocontents (ATS) and video contents (VTS). This playback apparatuscomprises: management information extraction means (30, 50 to 54) forextracting contents (ATT_SRP in FIG. 20) of the audio managementinformation (AMGI) from the digital information medium (10); audiocontents extraction means (30, 50 to 54, 60) for extracting contents(audio cells and the like in FIG. 7) of the audio contents (ATS) on thebasis of the contents (ATT_SRP for AOTT in FIG. 20) of the audiomanagement information (AMGI); and video contents extraction means (30,50 to 54, 58) for extracting contents (video cells in FIG. 8) of thevideo contents (VTS) on the basis of other contents (ATT_SRP for AVTT inFIG. 20) of the audio management information (AMGI).

The playback apparatus of the second object can play back a digitalinformation medium (AV disc 10) which contains audio data (AOTT_AOB)digitally converted by a predetermined sampling frequency (e.g., 192kHz) selected from a plurality of different sampling frequencies (48kHz, 96 kHz, 192 kHz, and the like) and a predetermined number ofquantization bits (e.g., 20 bits) selected from a plurality of differentnumbers of quantization bits (16 bits, 20 bits, 24 bits, and the like),and attribute information (AOTT_AOB_ATR in FIG. 25 included in ATSI inFIG. 24) indicating the predetermined sampling frequency (e.g., 192 kHz)and the predetermined number of quantization bits (e.g., 20 bits) usedfor this audio data (AOTT_AOB). In this playback apparatus, themanagement information extraction means (50) detects the predeterminedsampling frequency (e.g.r 192 kHz) and the predetermined number ofquantization bits (e.g., 20 bits) from the attribute information(AOTT_AOB_ATR), and the apparatus further comprises display means (4B)for displaying (the right end on FL display unit 4B in FIG. 30) thedetected predetermined sampling frequency (e.g., 192 kHz) andpredetermined number of quantization bits (e.g., 20 bits).

In order to achieve the third object, in a recording method according tothe present invention, upon recording information on an informationrecording medium (10) having a volume space (28) including an audio zone(71) and video zone (72) located after the audio zone (71), audiomanagement information (AMG) and audio contents (ATS) are recorded onthe audio zone (71), and video management information (VMG) and videocontents are recorded on the video zone (72).

In order to achieve the fourth object, in a playback method according tothe present invention, upon playing back information from an informationrecording medium (10) on which an audio zone (71) which records audiomanagement information (AMG) and audio contents (ATS), and a video zone(72) which records video management information (VMG) and video contents(VTS) are recorded, the audio contents (ATS) or video contents (VTS) areaccessed on the basis of the audio management information (AMG) to playback their contents, and the video contents are accessed on the basis ofthe video management information (VMG) to play back their contents.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view for explaining the structure of an opticaldisc which can be used as a recording medium of DVD audio;

FIG. 2 is a view for explaining the correspondence between a datarecording area and recording tracks of data recorded there in theoptical disc shown in FIG. 1;

FIG. 3 is a view for explaining the hierarchical structure ofinformation recorded in a DVD audio zone of various kinds of informationrecorded on the optical disc shown in FIG. 2;

FIG. 4 is a view for explaining the hierarchical structure ofinformation recorded in a DVD video zone of various kinds of informationrecorded on the optical disc shown in FIG. 2;

FIG. 5 is a view for explaining an example of video information (VTS_C#2or the like) which is commonly accessed from both program chaininformation (ATS_PGCI) in the DVD audio zone in FIG. 3 and program chaininformation (VTS_PGCI) in the DVD video zone shown in FIG. 4;

FIG. 6 is a view for explaining an example of the data structure of therecording contents (AOTT_AOBS) in the DVD audio zone shown in FIG. 3;

FIG. 7 is a view for explaining another example of the data structure ofthe recording contents (AOTT_AOBS) in the DVD audio zone shown in FIG.3;

FIG. 8 is a view for explaining an example of the data structure of therecording contents (VTSTT_VOBS) in the DVD video zone shown in FIG. 4;

FIG. 9 is a view for explaining an example of the data structure of theuser accessible DVD audio recording contents recorded on one face of theoptical disc shown in FIG. 1;

FIG. 10 is a view for explaining an example of the directory structureof information (DVD audio and video data files) recorded on the opticaldisc shown in FIG. 1;

FIG. 11 is a view for explaining another example of the directorystructure of information (DVD audio and video data files) recorded onthe optical disc shown in FIG. 1;

FIG. 12 is a view for explaining an access from a directory on the audiocontents side to files in a directory on the video contents side in thedirectory structure shown in FIG. 10;

FIG. 13 is a view for explaining a link of a file in a directory on theaudio contents side to that in a directory on the video contents side inthe directory structure shown in FIG. 10;

FIG. 14 is a view for explaining an example of the file access processin FIG. 12 in a volume space shown in FIGS. 3 and 4;

FIG. 15 is a view for explaining another example of the file accessprocess in FIG. 12 in the volume space shown in FIGS. 3 and 4;

FIG. 16 is a view for explaining still another example of the fileaccess process in FIG. 12 in the volume space shown in FIGS. 3 and 4;

FIG. 17 is a view for explaining the recording contents of audio managerinformation (AMGI) in the DVD audio zone shown in FIG. 3;

FIG. 18 is a view for explaining the recording contents of an audiomanager information management table (AMGI_MAT) included in the audiomanager information (AMGI) shown in FIG. 17;

FIG. 19 is a view for explaining the contents of an audio title searchpointer table (ATT_SRPT) included in the audio manager information(AMGI) shown in FIG. 17;

FIG. 20 is a view for explaining the contents of an audio title searchpointer (ATT_SRP) included in the audio title search pointer table(ATT_SRPT) shown in FIG. 19;

FIG. 21 is a view for explaining the contents of an audio only titlesearch pointer table (AOTT_SRPT) included in the audio managerinformation (AMGI) shown in FIG. 17;

FIG. 22 is a view for explaining the contents of an audio only titlesearch pointer (AOTT_SRP) included in the audio only title searchpointer table (AOTT_SRPT) shown in FIG. 21;

FIG. 23 is a view for explaining the relationship between an audio onlytitle group (AOTT_GR) accessed by the audio only search pointer(AOTT_SRP) in the audio manager information (AMGI) shown in FIG. 17, andan audio title group (ATT_GR) accessed by the audio title search pointer(ATT_SRP) in that audio manager information (AMGI);

FIG. 24 is a view for explaining the recording contents of an audiotitle set (ATS) in the DVD audio zone shown in FIG. 3;

FIG. 25 is a view for explaining the recording contents of audio titleset information management table (ATSI_MAT) included in audio title setinformation (ATSI) shown in FIG. 24;

FIG. 26 is a view for explaining the contents of an audio title setprogram chain information table (ATS_PGCIT) included in the audio titleset information (ATSI) shown in FIG. 24;

FIG. 27 is a view for explaining the contents of audio title set programinformation (ATS_PGI) shown in FIG. 26;

FIG. 28 is a view for explaining the contents of audio title set cellplayback information (ATS_C_PBI) shown in FIG. 26;

FIG. 29 is a block diagram showing an example of an apparatus forplaying back information recorded in the audio zone shown in FIG. 3 orthe video zone shown in FIG. 4 from the optical disc shown in FIG. 1;

FIG. 30 is a view showing an example of a front panel of the playbackapparatus shown in FIG. 29;

FIG. 31 is a plan view of a double-layered optical disc according to anembodiment of the present invention when viewed from the read laserreceiving face side;

FIG. 32 is a partial schematic sectional view of the double-layeredoptical disc shown in FIG. 31;

FIG. 33 is a partial schematic sectional view showing a modification ofFIG. 32, in which two-substrate-joined optical disc OD has a singleinformation recording layer;

FIG. 34 is a partial schematic sectional view showing anothermodification of FIG. 32, in which two-substrate-joined optical disc ODhas a single information recording layer;

FIG. 35 is a graph showing changes in allowable range of the thickness(ordinate) of a substrate to be joined as a function of the refractiveindex (abscissa) of a substrate material, when coherent light having awavelength of 650 nm is used and a pair of substrates each having asingle substrate/single recording layer structure are used; and

FIG. 36 is a graph showing changes in allowable range of the thickness(ordinate) of a substrate to be joined as a function of the refractiveindex (abscissa) of a substrate material, when coherent light having awavelength of 650 nm is used and a pair of substrates each having asingle substrate/dual recording layer structure are used.

BEST MODE OF CARRYING OUT THE INVENTION

A digital information recording/playback system according to anembodiment of the present invention will be described hereinafter withreference to the accompanying drawings.

FIG. 1 is a perspective view for explaining the structure of an opticaldisc that can be used as a recording medium of DVD audio.

As shown in FIG. 1, this optical disc 10 has a structure obtained byadhering a pair of transparent substrates 14 each having recording layer17 using adhesive layer 20. Each substrate 14 can be formed of a 0.6-mmthick polycarbonate film, and adhesive layer 20 can consist of a verythin (e.g., 40 to 70 μm thick) ultraviolet setting resin. When the pairof 0.6-mm thick substrates 14 are adhered to each other so that theirrecording layers 17 contact each other on the faces of adhesive layer20, a 1.2-mm thick large-amount optical disc 10 is obtained.

Optical disc 10 has center hole 22, and clamp areas 24 used for clampingoptical disc 10 upon its rotation are formed around center hole 22 onthe two faces of the disc. Center hole 22 receives the spindle of a discmotor when disc 10 is loaded into a disc drive (not shown). Optical disc10 is clamped at its clamp areas 24 by a disc clamper (not shown).

Optical disc 10 has information areas 25 that can record video data,audio data, and other information around clamp areas 24.

Each information area 25 has lead-out area 26 on its outer peripheryside, and lead-in area 27 on its inner periphery side that contactsclamp area 24. The area between lead-out and lead-in areas 26 and 27 isdefined as data recording area 28.

On recording layer (optical reflection layer) 17 of information area 25,a recording track is continuously formed in, e.g., a spiral pattern. Thecontinuous track is divided into a plurality of physical sectors, whichhave serial numbers. Various data are recorded on optical disc 10 usingthese sectors as recording units.

Data recording area 28 serves as an actual data recording area, andincludes an audio data recording area, and DVD video data recordingarea. (In case of a pure audio disc, the DVD video data recording areamay not be used.)

The DVD audio data recording area mainly records audio data as pittrains (physical shapes or phase states that bring about change inoptical conditions) as recording/playback information. In some cases,the DVD audio data recording area may record still picture data. Theaudio data recorded on this DVD audio data recording area can containsilent data (not a silent part of music but data which does not produceany sound intentionally) in addition to normal music data.

On the other hand, the DVD video data recording area records, asrecording/playback information, video data (main picture data) such as amovie or the like, sub-picture data such as superimposed dialogs, menus,and the like, and audio data such as words, effect sounds, and the likeas similar pit trains.

When optical disc 10 is a double-sided recording RAM disc (or arewritable disc; DVD-RW disc) in which each face has one recordinglayer, each recording layer 17 can be formed by three layers, i.e., bysandwiching a phase-change recording material layer (e.g., Ge₂Sb₂Te₅)between two zinc sulfide-silicon oxide (ZnS.SiO₂) mixture layers.

When optical disc 10 is a single-sided recording RAM disc in which eachface has one recording layer, recording layer 17 on the side of read-outface 19 can be formed by three layers including the phase-changerecording material layer. In this case, layer 17 on the side opposite toread-out face 19 need not be an information recording layer but maymerely be a dummy layer.

When optical disc 10 is a one-side read type double-layered RAM/ROMdisc, two recording layers 17 can comprise a single phase-changerecording layer (on the side further from read-out face 19; read/write),and a single semi-transparent metal reflection layer (on the side closerto read-out face 19; read-only).

When optical disc 10 is a write-once DVD-R, a polycarbonate substrate isused, gold can be used as a reflection layer (not shown), and anultraviolet setting resin can be used as a protection layer (not shown).In this case, an organic dye is used in recording layer 17. As theorganic dyes, cyanine, squarilium, chroconic, and triphenylmenthanedyes, xanthene and quinone dyes (naphthoquinone, anthraquinone, and thelike), metal complex dyes (phthalocyanine, porphyrin, dithiol complex,and the like), and so forth can be used.

Data can be written on such DVD-R disc using a semiconductor laserhaving a wavelength of 650 nm and an output of about 6 to 12 mW.

When optical disc 10 is a one-side read type double-layered ROM disc,two recording layers 17 can be comprised of a single metal reflectionlayer (on the side further from read-out face 19) and a singlesemi-transparent reflection layer (on the side closer to read-out face19).

In case of read-only DVD-ROM disc 10, pit trains are pre-formed by astamper on substrate 14, and a reflection layer of, e.g., a metal, isformed on that face of substrate 14, which is formed with pit trains.The reflection layer is used as recording layer 17. In such DVD-ROM disc10, no grooves serving as recording tracks are especially formed, andthe pit trains formed on the face of substrate 14 serve as tracks.

In various types of optical discs 10 described above, read-only ROMinformation is recorded on recording layer 17 as an embossed patternsignal. By contrast, no such embossed pattern signal is formed onsubstrate 14 having read/write (or write-once) recording layer 17, and acontinuous groove is formed instead. A phase-change recording layer isformed on such groove. In case of a read/write DVD-RAM disc, thephase-change recording layer in land portions is also used forinformation recording in addition to the groove.

When optical disc 10 is of one-side read type (independently of one ortwo recording layers), substrate 14 on the rear side viewed fromread-out face 19 need not always be transparent to the read/write laserbeam used. In this case, a label may be printed on the entire face ofsubstrate 14 on the rear side.

FIG. 2 is a view for explaining the correspondence between datarecording area 28 and recording tracks of data recorded there on opticaldisc 10 shown in FIG. 1.

When disc 10 is a DVD-RAM (or DVD-RW), disc 10 itself is stored in acartridge (not shown) to protect its delicate disc surface. When DVD-RAMdisc 10 in the cartridge is inserted into the disc drive of a DVD player(FIGS. 29 and 30), disc 10 is pulled out from the cartridge, is clampedby the turntable of a spindle motor (not shown), and is rotated to facean optical head (not shown).

On the other hand, when disc 10 is a DVD-R or DVD-ROM, disc 10 itself isnot stored in the cartridge, and bare disc 10 is directly set on thedisc tray of a disc drive.

Recording layer 17 of information area 25 shown in FIG. 1 is formed witha continuous data recording track in a spiral pattern. The continuoustrack is divided into a plurality of logical sectors (minimum recordingunits) each having a given storage amount, as shown in FIG. 2, and dataare recorded with reference to these logical sectors. The recordingamount per logical sector is determined to be 2,048 bytes (or 2 kbytes)which are equal to the data length of one pack.

Data recording area 28 is an actual data recording area, which recordsmanagement data and audio data for DVD audio, and similarly recordsmanagement data, main picture (video) data, sub-picture data, and audiodata for DVD video.

When disc 10 shown in FIG. 2 is a DVD-RAM disc, its data recording area28 can be divided into a plurality of ring-shaped (annular) recordingareas (a plurality of recording zones), although not shown. The angularvelocity upon rotation of the disc varies in units of recording zones.However, within each zone, a constant linear or angular velocity can beset. When disc 10 shown in FIG. 2 is a DVD-ROM disc, various data arerecorded on the entire data recording area 28 at a constant linearvelocity.

FIG. 3 is a view for explaining the hierarchical structure ofinformation recorded in the DVD audio zone of various kinds ofinformation recorded on optical disc 10 shown in FIG. 2.

Data recording area 28 formed on optical disc 10 shown in FIG. 2 has astructure, as shown in FIG. 3. The logical format of this structure isdefined to comply with, e.g., the Universal Disc Format (UDF) Bridge (ahybrid of UDF and ISO9660) as one of standard formats.

Data recording area 28 between lead-in area 27 and lead-out area 26 isassigned as a volume space. Volume space 28 can include a space forinformation of the volume and file structures (volume/file structure70), a space for the application of the DVD format (DVD audio zone 71and DVD video zone 72), and a space for an application other than thatof this format (other recording area 73).

Volume space 28 is physically divided into a large number of sectors,and these physical sectors have serial numbers. The logical addresses ofdata recorded on this volume space (data recording area in FIG. 2) 28mean logical sector numbers, as defined by the UDF Bridge. The logicalsector size in this space is 2,048 bytes (or 2 kbytes) as in thephysical sector size. The logical sector numbers are assigned serialnumbers in ascending order of physical sector numbers.

Unlike the logical sectors, each physical sector is added with redundantinformation such as error correction information and the like. For thisreason, the physical sector size does not strictly match the logicalsector size.

As shown in FIG. 3, volume space 28 includes volume/file structure area70, DVD audio zone 71, DVD video zone 72, and other recording area 73.These areas (70 to 73) are split up on the boundaries of logical sectorsin FIG. 2. Note that one logical sector is defined to be 2,048 bytes,and one logical block is also defined to be 2,048 bytes. Hence, onelogical sector is defined equivalently with one logical block.

Volume/file structure area 70 corresponds to a management area definedby the UDF Bridge. Based on the description of this area 70, thecontents of audio manager 711 are stored in an internal system memory ofthe DVD player (FIG. 29; to be described later).

DVD audio zone 71 consists of audio manager (AMG) 711 and one or moreaudio title sets (ATS#m) 712 (the maximum number m of audio title setsis 99).

AMG 711 is comprised of audio manager information (AMGI) file 7110,video object set (AMGM_VOBS) file 7111 for an audio manager menu, andaudio manager information backup (AMGI_BUP) file 7112. Note thatAMGM_VOBS 7111 is an optional file, and is not present in some cases.

Each ATS 712 is comprised of audio title set information (ATSI) file7120, audio object set (AOTT_AOBS) file 7121 for an audio only title,and audio title set information backup (ATSI_BUP) file 7123. Note thatAOTT_AOBS 7121 consists of one to nine files, which are optional filesand are not present in some cases.

As will be described later with reference to FIG. 6, AOTT_AOBS 7121defines a set of one or more audio objects AOB. Each AOB defines a setof one or more audio title set cells (ATS_C#). A set of one or morecells make up an audio title set program, and a set of one or moreprograms make up audio title set program chain PGC.

Considering one PGC as a single opera, a plurality of cells that formthis PGC can be explained as music pieces or song parts of variousscenes in that opera. The contents of this PGC (or the contents of eachcell) are determined by the software provider who produces the contentsrecorded on disc 10. More specifically, the provider can program to playback cells that form AOTT_AOBS 7121 using cell playback informationATS_C_PBI written in program chain information ATS_PGCI in ATS as he orshe intended. (ATS_PGCI and ATS_C_PBI will be explained later withreference to FIGS. 24 to 28.)

Other recording area 73 can record information that can be used in videotitle sets VTS 72 mentioned above or other kinds of information that donot pertain to video title sets. This area 73 is not mandatory, and maybe deleted if it is not used.

FIG. 4 is a view for explaining the hierarchical structure ofinformation recorded in the DVD video zone of various kinds ofinformation recorded on the optical disc shown in FIG. 2. An explanationpertaining to DVD video zone 72 will be given below except for thatalready described with reference to FIG. 3.

Based on the description of volume/file structure area 70, the contentsof video manager 721 are stored in the internal system memory of the DVDplayer (FIG. 29; to be described later).

DVD video zone 72 is comprised of video manager (VMG) 721 and one ormore video title sets (VTS#n) 722 (the maximum number n of video titlesets is 99).

VMG 721 consists of video manager information (VMGI) file 7210, videoobject set (VMGM_VOBS) file 7221 for a video manager menu, and videomanager information backup (VMGI_BUP) file 7212. Note that VMGM_VOBS7211 is an optional file, and is not present in some cases.

Each VTS 722 is comprised of video title set information (VTSI) file7220, video object set (VTSM_VOBS) file 7221 for a video title set menu,video object set (VTSTT_VOBS) file 7222 for a video title set title, andvideo title set information backup (VTSI_BUP) file 7223. Note thatVTSM_VOBS 7221 is an optional file, and is not present in some cases.

Each video title set VTS 72 stores video data (video pack to bedescribed later) compressed by MPEG, audio data compressed by apredetermined format or uncompressed audio data (audio pack),runlength-compressed sub-picture data (sub-picture pack to be describedlater; including bitmap data, each pixel of which is defined by aplurality of bits), and also information for playing back these data(navigation pack to be described later; including presentation controlinformation and data search information).

As will be described later with the aid of FIG. 8, VTSTT_VOBS 7222defines a set of one or more video objects VOB. Each VOB defines a setof one or more video title set cells (VTS_C#). A set of one or morecells make up a video title set program, and a set of one or moreprograms make up a video title set program chain.

Assuming that one PGC corresponds to one drama, a plurality of cellsthat make up this PGC can correspond to various scenes in that drama.The contents of the PGC (or those of cells) are determined by, e.g., asoftware provider who produces the contents recorded on disc 10. Morespecifically, as in ATS_PGCI described above with reference to FIG. 3,the provider can program to play back cells that form VTSTT_VOBS 7222using cell playback information (not shown) written in program chaininformation VTS_PGCI in VTS as he or she intended.

FIG. 5 is a view for explaining common accesses to specific videoinformation (VTS_C#2, VTS_C#3, VTS_C#5) from program chain informationATS_PGCI in the DVD audio zone in FIG. 3 and program chain informationVTS_PGCI in the DVD video zone in FIG. 4 (but by different methods). Inother words, FIG. 5 exemplifies a case wherein single video object VOBis referred to by different methods from playback units on both theaudio and video sides.

More specifically, upon video playback from the video title set side,cells VTS_C#1 to VTS_C#6 in VOB are played back in turn in accordancewith cell playback information (not shown) in VTS_PGCI.

On the other hand, upon video playback (or still playback) from theaudio title set side, cells VTS_C#2, VTS_C#3, and VTS_C#5 in VOB areselectively played back in accordance with cell playback information(FIG. 28) in ATS_PGCI.

In this case, since ATS and VTS need not independently have identicalcell data (VTS_C#2, VTS_C#3, and VTS_C#5) in single disc 10, the limitedresource of disc 10 can be effectively used.

FIG. 6 shows an example of the data structure of the recording contents(AOTT_AOBS) in the DVD audio zone shown in FIG. 3.

AOTT_AOBS 7121 described above with the aid of FIG. 3 defines a set ofone or more audio objects AOTT_AOB#, as shown in FIG. 6. A set of one ormore cells ATS_C# form a program, and a set of one or more programs formprogram chain PGC. This PGC forms a logical unit indicating the entireor partial audio title.

In the example shown in FIG. 6, each audio cell ATS_C# is comprised of aset of audio packs A_PCK each having a 2,048-byte size. These packsserve as minimum units upon data transfer. On the other hand, theminimum unit for logical processing is a cell, and the logicalprocessing is done in units of cells.

FIG. 7 shows another example of the data structure of the recordingcontents (AOTT_AOBS) in the DVD audio zone shown in FIG. 3. In theexample shown in FIG. 7, the cell and pack formats are different fromthose in FIG. 6.

More specifically, audio object AOTT_AOB#1 shown in FIG. 7 containspicture cell ATS_C#1, silent cell ATS_C#2, audio cell ATS_C#3, and thelike. The next AOTT_AOB#2 may contain audio cells ATS_C alone, althoughnot shown. The audio object mainly contains audio cells, but a picturecell and/or silent cell are/is appended appropriately.

Picture cell ATS_C#1 may consist of one or more still picture packsSPCT_PCK, and silent cell ATS_C#2 may consist of one or more silentaudio packs A_PCK. The playback time of the silent cell is set at about0.5 sec or more. Audio cell ATS_C#3 consists of audio packs A_PCK andalso appropriately contains real time information packs RTI_PCK havingreal time information.

Upon data transfer of still picture pack SPCT_PCK during playback of aDVD audio player, sound is interrupted for a short period of time (about0.5 sec to 0.6 sec) during transfer. This sound interruption is calledan audio gap. Since it is inconvenient if an audio gap is produced inthe middle of music playback, still picture pack SPCT_PCK is normallytransferred before the beginning of album playback in FIG. 9, before thebeginning of playback of a specific group, or before the beginning of aspecific track.

Once still picture pack SPCT_PCK has been transferred inside the DVDaudio player, a still picture corresponding to the contents of thisSPCT_PCK is held in a picture memory in the player. The still picture inthis memory can be continuously played back during playback of thecontents (music or the like) of audio packs A_PCK (the still picture canbe cleared from the monitor any time the user desires).

FIG. 8 shows an example of the data structure of the recording contents(VTSTT_VOBS) in the DVD video zone shown in FIG. 4.

VTSTT_VOBS described above using FIG. 4 defines a set of one or morevideo objects VOB#, as shown in FIG. 8. Each VOB defines a set of one ormore cells VTS_C#. Each VTS_C defines a set of one or more video objectunits VOBU. A set of one or more cells VTS_C# make up a program, and aset of one or more programs make up program chain PGC. This PGC forms alogical unit indicating the entire or partial audio title.

As shown in FIG. 8, each VOBU is constituted as a set (pack sequence) ofvideo packs (MPEG-compressed moving picture data), sub-picture packs(runlength-compressed bitmap data), and audio packs (non-compressedlinear PCM audio data or compressed multichannel audio data) to have anavigation pack at the beginning of the sequence. That is, video objectunit VOBU is defined as a set of all packs recorded from a certainnavigation pack to a pack immediately before the next navigation pack.This navigation pack is built in each video object unit VOBU to realizeangle change (non-seamless angle change playback and seamless anglechange playback).

Each of these packs serves as a minimum unit for data transfer as inFIG. 6 or 7. The minimum unit for logical processing is a cell, andlogical processing is done is units of cells.

The playback time of VOBU corresponds to that of video data made up ofone or more picture groups (groups of pictures; to be abbreviated asGOPs), and is set to fall within the range from 0.4 sec to 1.2 sec. OneGOP is screen data which normally has a playback time of about 0.5 secin the MPEG format, and is compressed to play back approximately 15pictures during this interval.

When VOBU includes video data, a video datastream is formed by arrangingGOPs (complying with MPEG) each consisting of video packs, sub-picturepacks, and audio packs. However, independently of the number of GOPs,VOBU is defined with reference to the playback time of GOPs, and anavigation pack is always set at the beginning of VOBU.

Upon playback for DVD video, even playback data consisting of audio dataand/or sub-picture data alone is formed using VOBU as one unit. Forexample, assume that VOBU is formed by audio packs alone to have anavigation pack at its beginning. In this case, the audio packs to beplayed back in the playback time (0.4 sec to 1.2 sec) of VOBU to whichthe audio data belong are stored in that VOBU as in VOB of video data.

As shown in FIG. 8, VTSTT_VOBS is defined as a set of one or more VOBs,and VOBs in this VOBS are used for the same purpose.

VOBS for menus normally consists of one VOB, which stores a plurality ofmenu screen display data. By contrast, VOBS for a title set normallyconsists of a plurality of VOBs.

Taking a concert video title of a certain rock band as an example, VOBsthat form video object set VTSTT_VOBS for a title set correspond topicture data of the performance of that band. In this case, bydesignating given VOB, for example, the third tune in the concert of theband can be played back.

VOB that forms video object set VTSM_VOBS for menus stores menu data ofall the tunes performed in the concert of the band, and a specific tune,e.g., an encore, can be played back according to the menu display.

Note that one VOB can form one VOBS in a normal video program. In thiscase, a single video stream comes to an end in one VOB.

On the other hand, in case of a collection of animations having aplurality of stories or an omnibus movie, a plurality of video streams(a plurality of video chains PGC) can be set in single VOB incorrespondence with the respective stories. In this case, the individualvideo streams are stored in corresponding VOBs. An audio stream andsub-picture stream pertaining to each video stream end in correspondingVOB.

Video objects VOB are assigned identification numbers (#i; i=0 to i),and that VOB can be specified by the identification number. VOB consistsof one or more cells. A normal video stream consists of a plurality ofcells, but a video stream for menus often consists of single cell. Thecells are assigned identification numbers (#j; j=0 to j) as in VOBs.

FIG. 9 shows the recording contents of user accessible DVD audio zone71, i.e., an example of the data structure recorded on one side (single-or double-layered) of the optical disc in FIG. 1.

In DVD audio, the hierarchical structure defined by an album, groups,tracks, and indices is prepared as the management structure for therecording contents viewed from the software production side.

The album corresponds to one side of DVD audio disc 10, and for example,“Vol. 1 of works of Beethoven” can be assigned to this album. In suchcase, this album may be made up of group #1 of Symphony No. 1 to group#9 of Symphony No. 9.

Each group (e.g., group #1) is made up of tracks #1 to #4 correspondingto the first to fourth movements of the corresponding symphony (SymphonyNo. 1). Furthermore, each track is comprised of indices #1 to #iobtained by dividing the contents of the track into i pieces.

When the user plays back DVD audio disc 10 produced with thehierarchical structure shown in FIG. 9, the user sets that disc 10 onthe DVD audio player (FIGS. 29 and 30), and then can select group #1 andtrack #1 by operating a remote controller (not shown).

After this selection, when the user presses the playback button of theremote controller, the DVD audio player starts playback from thebeginning of the first movement of Symphony No. 1 of Beethoven.Furthermore, when the user designates a specific index using the remotecontroller, the designated index part is reached by search, and playbackrestarts from that part. (The first index part of the first track of thefirst group in that album can be played back as a default without anyuser's designation.)

Note that the user can recognize a title (e.g., a specific movie titleor the like) in case of playback of a DVD video disc. However, in caseof a DVD audio disc, the user cannot see the “title”. The user can onlysee “album”, “group”, “track”, and “index” shown in FIG. 9.

FIG. 10 shows the directory structure of information (DVD audio andvideo data files) recorded on the optical disc shown in FIG. 1. FIG. 10shows an example of the file directory structure defined by the DVD fileformat.

As in the hierarchical file structure used by a versatile operatingsystem of a computer, the subdirectory of video title set VTS and thatof audio title set ATS, the user-defined directory, and the like arelocated in succession under the root directory.

Various video files (files VMGI, VMGM, VTSI, VTSM, VTS, and the like;see FIG. 4) are located in the subdirectory of video title set VTS tomanage the individual files systematically.

Also, various audio files (files AMGI, ATSI, ATS, and the like; see FIG.3) are located in the subdirectory of audio title set ATS to manage theindividual files systematically.

The user can access a specific file (e.g., specific VTS or ATS) bydesignating the path from the root directory to that file.

Upon playing back a DVD video disc created according to the DVD videoformat, a DVD video player manufactured according to the DVD videoformat reads management information (VMG) located in the video title setVTS directory beneath the root directory first, and plays backs videocontents in accordance with that information. However, VMG can only playback the video contents (VTS) recorded in the VTS directory.

On the other hand, upon playing back a DVD audio disc created accordingto the DVD audio format, a DVD audio player (or a DVD-Video/DVD-Audiocompatible player) manufactured in accordance with the DVD audio formatreads management information (AMG) located in the audio title set ATSdirectory under the root directory, and plays back audio contents inaccordance with that information. In this case, AMG can play back notonly the audio contents (ATS) recorded in the ATS directory but also thevideo contents (VTS) in the VTS directory (this mechanism will beexplained later with reference to FIG. 12 and the subsequent figures).

FIG. 11 shows another example of the directory structure of information(DVD audio and video data files) recorded on the optical disc shown inFIG. 1.

In the example shown in FIG. 10, both the VTS and ATS directories arelocated on the same layer level under the root directory. On the otherhand, in the example shown in FIG. 11, the ATS directory (childdirectory) is located in a layer under the root directory (parentdirectory), and the VTS directory (grandchild directory) is located in alayer under the ATS directory.

FIG. 12 is a view for explaining an access from the directory on theaudio contents side to a file in the directory on the video contentsside in the directory structure shown in FIG. 10.

More specifically, in the hierarchical management structure for managingdata files recorded on AV disc 10, the video title set directory (childdirectory) and audio title set directory (child directory) are locatedunder the root directory (parent directory).

The video title set (VTS) directory manages files for the video contentsrecorded on disc 10, and contains a file of video manager VMG and one ormore files (logical units of the video contents) of video title sets VTS(see FIG. 4).

The audio title set (ATS) directory manages files for the audio contentsrecorded on disc 10, and contains a file of audio manager AMG and one ormore files (logical units of the audio contents) of audio title sets ATS(see FIG. 3).

VMG in the VTS directory manages VTS alone, and can only access VTS inthe VTS directory.

On the other hand, AMG in the ATS directory mainly manages ATS, but canaccess not only ATS in the ATS directory but also VTS in the VTSdirectory.

AMG contains audio manager information AMGI (FIG. 17), AMGI containsaudio title search pointer table ATT_SRPT (FIG. 17), and ATT_SRPTcontains audio only title (AOTT) search pointer ATT_SRP and audio video(AVTT) search pointer ATT_SRP (FIG. 20) (their contents will beexplained in detail later with reference to FIGS. 17 to 20).

More specifically, AMG in the ATS directory can access audio title setsATS#1, ATS#2, . . . in the ATS directory by AOTT search pointer ATT_SRP,and can also access video title sets VTS#1, VTS#2, . . . in the VTSdirectory by AVTT search pointer ATT_SRP. In this way, a certain object(e.g., VTS#1) can be shared by both the video and audio contents. Thisis one of important characteristic features of the “object sharingsystem” of the present invention.

FIG. 13 is a view for explaining a link from a file in the directory onthe audio contents side to that in the directory on the video contentsside in the directory structure shown in FIG. 10. FIG. 13 can beconsidered as a modification of FIG. 12.

More specifically, in the example shown in FIG. 12, since audio managerAMG is capable of accessing both audio title sets ATS and video titlesets VTS, a certain VTS can be shared by the video and audio contents.

On the other hand, in the example shown in FIG. 13, information (e.g., apointer indicating the address of a predetermined portion of VTS#1) forlinking to a certain video title set (VTS#1 in this case) is written ina certain audio set (ATS#1 in this case). With this information, audiodata in, e.g., VTS#1 can be shared by the video and audio contents.

FIG. 14 shows the data structure to explain an example of the fileaccess process in FIG. 12 in the volume space shown in FIGS. 3 and 4.The data structure shown in FIG. 14 corresponds to the directorystructure shown in FIG. 12.

Referring to FIG. 14, the hatched portions exemplify contents shared bythe video contents (or video volume) and audio contents (or audiovolume).

The principle of the data structure shown in FIG. 14 is to independentlyrecord the recording area (VMG+VTS) for the video contents and therecording area (AMG+ATS) for the audio contents in volume space 28, andto allow AMG to manage the video contents which are used not only forvideo but also commonly for audio.

For example, in FIG. 14, video title set VTS#1 managed by VMG can accessa portion (cell) in video object sets VOBS#1, while audio title setATS#1 managed by AMG can access another portion (cell) in VOBS#1. Inthis example, some cells (see FIG. 8) that make up video object setVOBS#1 of VTS#1 are shared by the video and audio contents.

In the data structure shown in FIG. 14, DVD audio zone 71 is located onthe side of smaller addresses (closer to lead-in area 27 in FIG. 3), andDVD video zone 72 is located on the side of larger addresses (closer tolead-out area 26 in FIG. 3). In this case, AMG can always use addressesthat change in the + direction (see arrows a and b) upon accessing bothATS and VTS, and need not use addresses in the − direction, resulting ineasy construction of the playback system.

FIG. 15 shows the data structure to explain another example of the fileaccess process in FIG. 12 in the volume space shown in FIGS. 3 and 4.FIG. 15 can be considered as a modification of FIG. 14.

In FIG. 14, since the DVD audio zone 71 is located on the side ofsmaller addresses, and DVD video zone 72 is located on the side oflarger addresses, the addresses in the − direction need not be used, asdescribed above.

On the other hand, in FIG. 15, DVD video zone 72 is located on the sideof smaller addresses (closer to lead-in area 27 in FIG. 3), and DVDaudio zone 71 is located on the side of larger addresses (closer tolead-out area 26 in FIG. 3). In such case, AMG uses the address in the +direction to access ATS, and uses the address in the − direction toaccess VTS. That is, addressing upon accessing a desired object (cellsin ATS or VTS) is cumbersome, and it is inappropriate to use suchaddress allocation in home-use DVD audio players that require lowmanufacturing cost.

However, when a personal computer having a DVD drive is used as a DVDaudio player with the help of software, the cost problem can be avoidedeven when the data structure shown in FIG. 15 is used. That is, anoperating system (or control software) on the personal computer, whichhas interpreted the data structure shown in FIG. 15, can re-map theaddresses onto its own memory and can apparently convert the datastructure physically having the address allocation shown in FIG. 15 intothat shown in FIG. 14. In this way, an MPU or CPU of that personalcomputer allows AMG to access both ATS and VTS by designating addressesin the +direction alone as in FIG. 14.

FIG. 16 shows the data structure to explain still another example of thefile access process in FIG. 12 in the volume space shown in FIGS. 3 and4. FIG. 16 can also be considered as a modification of FIG. 14.

In FIG. 14, since the DVD audio zone 71 is located on the side ofsmaller addresses, and DVD video zone 72 is located on the side oflarger addresses, the addresses in the − direction need not be used, asdescribed above.

By contrast, in the data structure shown in FIG. 16, AMG in DVD audiozone 71 is located on the side of smaller addresses (closer to lead-inarea 27 in FIG. 3), and VMG in DVD video zone 72 is located on the sideof larger addresses (closer to lead-out area 26 in FIG. 3) than AMG. Inthis case, AMG can always use addresses that change in the + directionto access both ATS and VTS, and need not use addresses in the −direction. For this reason, the playback system can be easilyconstructed as in FIG. 14.

However, since the data structure shown in FIG. 16 is a “nested”structure, i.e., VTS#1 and the like are located in ATS#1, VMG in FIG. 4cannot recognize that VTS in ATS is present in DVD video zone 72. Insuch case, VMG can handle that VTS in ATS as one in other recording area73.

The data structure shown in FIG. 16 can be used when AMG can access notonly ATS but also VTS using other recording area 73.

The three different examples shown in FIGS. 14 to 16 have been describedas those for the data structure in which “AMG can access both ATS andVTS”. The most preferred data structure is that shown in FIG. 14, sincea desired shared object can be accessed by only designating an addressin the + direction without re-mapping the addresses.

FIG. 17 is a view for explaining the recording contents of audio managerinformation AMGI in the DVD audio zone shown in FIG. 3.

DVD audio zone 71 can handle two different types of contents, i.e.,audio only title AOTT and audio title with video (or audio•video title)AVTT.

AOTT is a title in audio disc (A disc 10), has no video part, and isdefined by ATS recorded underneath the audio title set directory. On theother hand, AVTT is a title in audio disc (AV disc) 10, has video part,and is defined by VTS recorded underneath the video title set directory.The general name of AOTT and AVTT is defined as ATT (audio title).

DVD audio zone 71 on which the ATT data are recorded is made up of AMG711 and one or more (a maximum of 99) audio title sets (ATS#1 to ATS#m)712.

AMG 711 consists of audio manager information AMGI file 7110, videoobject set AMGM_VOBS file (optional file) 7111 for audio manager menus,and audio manager information backup AMGI_BUP file 7112.

AMGI file 7110 contains audio manager information management tableAMGI_MAT, audio title search pointer table ATT_SRPT, audio only titlesearch pointer table AOTT_SRPT, audio manager menu program chaininformation unit table AMGM_PGCI_UT, and audio text data managerATXTDT_MG.

More specifically, AMG has two pieces of search information ATT_SRPT andAOTT_SRPT. ATT_SRPT is a table that describes search information forboth AOTT and AVTT, and AOTT_SRPT is a table that describes searchinformation for AOTT alone.

The reason why the search information is prepared not for AVTT and AOTTbut for ATT (the general name of AOTT and AVTT) (ATT_SRPT in FIG. 20; tobe described later) and AOTT (AOTT_SRPT in FIG. 22; to be describedlater) is to facilitate the playback methods of various DVD players.

FIG. 18 shows the recording contents of audio manager informationmanagement table AMGI_MAT contained in audio manager information AMGIshown in FIG. 17.

More specifically, audio manager information management table AMGI_MATincludes: an audio manager identifier (AMG_ID); the end address (AMG_EA)of the audio manager; the end address (AMGI_EA) of the audio managerinformation; the version number (VERN) of the format used by opticaldisc (DVD audio disc) 10 of interest; a volume set identifier (VLMS_ID);auto play information (AP_INF) indicating the playback state after thedisc is loaded into the player; the start address (ASVS_SA) of audiostill video set ASVS, which address is expressed by the number ofrelative blocks from the first logical block of AMG; the number (TS_Ns)of title sets; an identifier (PVR_ID) of the provider (i.e., theproducer and distributor of software); the end address (AMGI_MAT_EA) ofthe audio manager information management table; the start address(AMGM_VOBS_SA) of an audio manager menu video object set; the startaddress (ATT_SRPT_SA) of the audio title search pointer table; the startaddress (AOTT_SRPT_SA) of the audio only title search pointer table; thestart address (AMGM_PGCI_UT_SA) of the audio manager menu program chaininformation unit table; the start address (ATXTDT_MG_SA) of the audiotext data manager; a video attribute (AMGM_V_ATR) for the audio managermenu video object set; the number (AMGM_SPST_Ns) of sub-picture streamsfor audio manager menus; a sub-picture attribute (AMGM_SPST_ATR) for theaudio manager menu video object set; the number (AMGM_AST_Ns) of audiostreams of audio manager menus; an audio attribute (AMGM_AST_ATR) forthe audio manager menu video object set; and other reserved areas.

In start address AMGM_VOBS_SA of the audio manager menu video objectset, the start address of AMGM_VOBS is written as the number of relativeblocks from the first logical block of AMG. If AMGM_VOBS does not exist,“000000001h” is written in this AMGM_VOBS_SA.

In start address ATT_SRPT_SA, the start address of ATT_SRPT is writtenas the number of relative blocks from the first logical block of AMGI.

In start address AOTT_SRPT_SA, the start address of AOTT_SRPT is writtenas the number of relative blocks from the first logical block of AMGI.

ATT_SRPT_SA or AOTT_SRPT_SA written in AMGI_MAT in FIG. 18 can indicatethe recording location of audio title search pointer table ATT_SRPT oraudio only title search pointer table AOTT_SRPT in disc 10.

FIG. 19 is a view for explaining the contents of audio title searchpointer table ATT_SRPT contained in audio manager information AMGI shownin FIG. 17. AMGI has two different search pointer tables ATT_SRPT andAOTT_SRPT, and FIG. 19 shows search pointer ATT_SRP that can access bothAOTT and AVTT.

More specifically, ATT_SRPT contained in AMGI includes audio titlesearch pointer table information ATT_SRPTI and one or more audio titlesearch pointers ATT_SRP (ATT_SRP#1 to ATT_SRP#n). ATT_SRPTI contains thenumber of audio title search pointers, and the end address of ATT_SRPT.

FIG. 20 is a view for explaining the contents of each audio title searchpointer (ATT_SRP#n in this case) included in audio title search pointertable ATT_SRPT shown in FIG. 19.

The DVD audio format handle use not only sound data but also picturedata, and AMG has two pieces of search information ATT_SRPT andAOTT_SRPT. ATT_SRPT shown in FIG. 20 is a table that describes searchinformation for both AOTT and AVTT.

Referring to FIG. 20, audio only title search pointer AOTT_SRP includescategory ATT_CAT of audio title ATT, number ATT_PG_Ns of programs in oneaudio title ATT, total playback time ATT_PB_TM of audio title ATT, audiotitle set ATS number ATSN, audio title set ATS title number ATS_TTN, andstart address ATS_SA of audio title set ATS.

Audio video title search pointer AVTT_SRP includes category ATT_CAT ofaudio title ATT, number ATT_PG_Ns of programs in one ATT, number AGL_Nsof angles included in video, total playback time ATT_PB_TM of audiotitle ATT, video title set VTS number VTSN, video title set VTS titlenumber VTS_TTN, and start address VTS_SA of video title set VTS.

FIG. 21 is a view for explaining the contents of audio only title searchpointer table AOTT_SRPT contained in audio manager information AMGIshown in FIG. 17. AMGI has two different search pointer tables ATT_SRPTand AOTT_SRPT, and FIG. 21 shows search pointer AOTT_SRP that can accessonly AOTT.

More specifically, AOTT_SRPT contained in AMGI includes audio only titlesearch pointer table information AOTT_SRPTI, and one or more audio onlytitle search pointers AOTT_SRP (AOTT_SRP#1 to AOTT_SRP#m). AOTT_SRPTIincludes number AOTT_SRP_Ns of audio only search pointers, and endaddress AOTT_SRPT_EA of AOTT_SRPT.

FIG. 22 is a view for explaining the contents of one audio only searchpointer (AOTT_SRP#m in this case) included in audio only title searchpointer table AOTT_SRPT shown in FIG. 21.

The DVD audio format handle use not only sound data but also picturedata, and AMG has two pieces of search information ATT_SRPT andAOTT_SRPT. AOTT_SRPT shown in FIG. 22 is a table that describes searchinformation for only AOTT.

More specifically, in FIG. 22, audio only title search pointer AOTT_SRPincludes category ATT_CAT of audio title ATT, number AOTT_PG_Ns ofprograms in one audio only title AOTT, total playback time AOTT_PB_TM ofaudio only title AOTT, audio title set ATS number ATSN, audio title setATS title number ATS_TTN, and start address ATS_SA of audio title setATS.

In control information of a playback title defined in audio manager AMG,title group TT_GR can be designated.

Title group TT_GR is a set of one or more audio titles ATT, and isdefined as a unit for guaranteeing continuous playback of an ATT group.On the user side, each audio title ATT corresponds to a “tune”, andtitle group TT_GR corresponds to an “album” as a set of tunes (see FIG.9). On a record or CD, when playback starts from the first or middletune of the album, that album can be continuously played back to itsend. Likewise, when playback starts from the first or middle ATT inTT_GR, playback continues to the end of this TT_GR.

As title group TT_GR, the following two groups can be defined.

<A1> Audio title group (ATT_GR); this ATT_GR is title group TT_GRconsisting of audio titles ATT defined in audio title search pointertable ATT_SRPT.

<A2> Audio only title group (AOTT_GR); this AOTT_GR is title group TT_GRconsisting of audio only titles AOTT defined in audio only searchpointer table AOTT_SRPT.

Audio title group ATT_GR is used for a player which can play backpicture and audio data complying with the audio format (i.e., a playerwhich can play back both AOTT and AVTT), and audio only title groupAOTT_GR is used for a player which can play back only audio datacomplying with the audio format (i.e., a player which can play back onlyAOTT).

Audio title ATT has the following three variations.

<B1> ATT has only AOTT.

<B2> ATT has only AVTT.

<B3> ATT has both AOTT and AVTT (in this case, ATT has AVTT and AOTTcorresponding to different versions (with and without a picture) of anidentical tune).

In case of <B1>, search information for AOTT is described in bothATT_SRPT and AOTT_SRPT (see FIGS. 20 and 22).

In case of <B2>, search information for AVTT is described in onlyATT_SRPT (see FIG. 20).

In case of <B3>, search information for AOTT is described in onlyAOTT_SRPT, and that for AVTT is described in only ATT_SRPT (see FIG.20).

FIG. 23 exemplifies the relationship among <B1> to <B3> above. That is,FIG. 23 exemplifies the relationship between audio only title groupAOTT_GR accessed by audio only title search pointer AOTT_SRP in audiomanager information AMGI shown in FIG. 17, and audio title group ATT_GRaccessed by audio title search pointer ATT_SRP in that audio managerinformation AMGI. In other words, FIG. 23 shows an example of therelationship between ATT_SRPT and AOTT_SRPT.

Referring to FIG. 23, audio titles ATT#1 and ATT#9 are made up of onlyaudio video titles AVTT, ATT#2 and ATT#3 of audio video titles AVTT andaudio only titles AOTT, and ATT#4, ATT#5, ATT#7, and ATT#8 of only audioonly titles AOTT.

In the example shown in FIG. 23, nine audio titles ATT are used, areclassified into four groups (GR#1 to GR#4) to form audio title groupsATT_GR, and are classified into two groups (GR#1 and GR#2) to form audioonly title groups AOTT_GR.

In this example, audio titles ATT#1 and ATT#9 consist of AVTT alone, anddo not include any AOTT. Hence, ATT#1 and ATT#9 do not exist as audioonly title group AOTT_GR.

For this reason, the number (four in this example) of audio title groupsATT_GR does not generally match that (two in this example) of audio onlytitle groups AOTT_GR.

It is necessary to maintain consistency of title group TT_GR uponplaying back an ATT group between a player which can play back pictureand audio data complying with the audio format (i.e., a player which canplay back both AOTT and AVTT), and a player which can play back onlyaudio data complying with the audio format (i.e., a player which canplay back only AOTT).

More specifically, even though corresponding ATT_GR and AOTT_GR havedifferent GR numbers, they should include identical ATTs and have thesame order of ATTs in TT_GR. Otherwise, the user is confused. Of course,in this case, ATTs (ATT#1 and ATT#9) which consist of AVTT alone butinclude no AOTT are excluded.

To meet this “demand”, “ATT not defined as AOTT” and “ATT defined asAOTT” are prevented from being present in single ATT_GR. In this way,the consistency in TT_GR can be maintained for ATTs included in bothATT_GR and AOTT_GR.

In the example shown in FIG. 23, ATT_GR#2 and AOTT_GR#1, and ATT_GR#3and AOTT_GR#2 are respectively made up of identical ATTs, and have thesame orders of ATT in TT_GR.

FIG. 24 is a view for explaining the recording contents of an audiotitle set (ATS) in the DVD audio zone shown in FIG. 3.

Audio title set ATS is made up of audio title set information ATSI,audio only title set audio object set AOTT_AOBS, and audio title setinformation backup ATSI_BUP.

Audio title set information ATSI includes audio title set managementtable ATSI_MAT, and audio title set program chain information tableATS_PGCIT.

Audio title set program chain information table ATS_PGCIT includes audiotitle set program chain information table information ATS_PGCITI, audiotitle set program chain information search pointer ATS_PGCI_SRP, and oneor more pieces of audio title set program chain information ATS_PGCI.

FIG. 25 shows the recording contents of audio title set informationmanagement table ATSI_MAT shown in FIG. 24.

More specifically, this audio title set information management tableATSI_MAT includes: an audio title set identifier (ATSI_ID); the endaddress (ATS_EA) of an audio title set; the end address (ATSI_EA) ofaudio title set information; the version number (VERN) of the audioformat used; the end address (ATSI_MAT_EA) of the audio title setinformation management table; the start address (VTS_SA) of audio onlytitle AOTT video title set VTS; the start address (AOTT_AOBS_SA) of anaudio only title audio object set or the start address (AOTT_VOBS_SA) ofan audio only title video object set; the start address (ATS_PGCIT_SA)of the audio title set program chain information table; attributes(AOTT_AOB_ATR) #0 to #7 of an audio only title audio object set orattributes (AOTT_VOB_ATR) #0 to #7 of an audio only title video objectset; coefficients (ATS_DM_COEFT) #0 to #15 to mix down audio data; andother reserved areas.

In start address VTS_SA of VTS for AOTT, the start address of VTSincluding VTSTT_VOBS (FIG. 8) used for AOTT is written when ATS has noAOTT_AOBS. On the other hand, when ATS has AOTT_AOBS, “00000000h” iswritten in VTS_SA.

In AOTT_AOBS_SA, the start address of AOTT_AOBS is written as the numberof relative logical blocks from the first logical block of ATS when ATShas AOTT_AOBS. On the other hand, when ATS has no AOTT_AOBS, the startaddress of VTSTT_VOBS is written as the number of relative logicalblocks from the first logical block of VTS that includes VTSTT_VOBS usedfor ATS.

In ATS_PGCIT_SA, the start address of ATS_PGCIT is written as the numberof relative logical blocks from the first logical block of ATSI.

Eight attributes #0 to #7 are prepared for AOTT_AOB_ATR or AOTT_VOB_ATR.When ATS has AOTT_AOBS, the attribute of AOTT_AOB written in ATS iswritten in AOTT_AOBS_ATR. On the other hand, when ATS has no AOTT_AOBS,the attribute of an audio stream in VOB used for AOTT_VOB in ATS iswritten in AOTT_VOB_ATR. In AOTT_AOB_ATR or AOTT_VOB_ATR, the samplingfrequency (44 to 192 kHz) used and the number of quantization bits (16to 24 bits) are written.

ATS_DM_COEFT indicates a coefficient upon mixing down audio data havingmultichannel outputs (5.1-channel outputs) like in AC-3, DTS, or thelike to 2-channel outputs, and is used in only one or more AOTT_AOBsrecorded in ATS. When ATS has no AOTT_AOBS, “0h” is written in all thebits of 16 coefficients ATS_DM_COEFT (#0 to #15). Areas for these 16coefficients ATS_DM_COEFT (#0 to #15) are steadily assured.

Each ATS_SPCT_ATR has a 16-bit configuration: 2 bits (bits b15 and b14)on the MSB side represent a video compression mode (MPEG2 or the like);the next 2 bits (bits b13 and b12) a TV system (NTSC, PAL, SECAM, or thelike); the next 2 bits (bits b11 and b10) the aspect ratio (4:3, 16:9,or the like) of a picture; and the next 2 bits (bits b9 and b8) adisplay mode (4:3 display, 16:9 display, letter box display, or the likeon a TV monitor having a 4:3 size). The next 2 bits (bits b7 and b6) arereserved bits for the future. The next 3 bits (bits b5 to b3) representthe resolution (720 lines in the horizontal direction×480 lines in thevertical direction in the NTSC system), 720 lines in the horizontaldirection×576 lines in the vertical direction in the PAL system, or thelike) of a still picture. The last 3 bits (bits b2 to b0) on the LSBside are reserved bits for the future.

FIG. 26 is a view for explaining the contents of audio title set programchain information table ATS_PGCIT included in audio title setinformation ATSI shown in FIG. 24 (the recording location of thisATS_PGCIT is written in ATS_PGCIT_SA in ATSI_MAT shown in FIG. 25).

This ATS_PGCIT contains audio title set program chain information tableinformation ATS_PGCITI, audio title set program chain information searchpointer ATS_PGCI_SRP, and audio title set program chain informationATS_PGCI, as described above.

ATS_PGCI_SRP includes one or more audio title set program chaininformation search pointers (ATS_PGCI_SRP#1 to ATS_PGCI_SRP#j), andATS_PGCI includes the same number of pieces of audio title set programchain information (ATS_PGCI#1 to ATS_PGCI#j) as that of pointersATS_PGCI_SRP.

Each ATS_PGCI serves as navigation data for controlling playback ofaudio title set program chain ATS_PGC.

Note that ATS_PGC is a unit for defining audio only title AOTT, and ismade up of ATS_PGCI and one or more cells (those in AOTT_AOBS or thosein AOTT_VOBS used as an object for AOTT).

Each ATS_PGCI contains audio title set program chain general information(ATS_PGC_GI), an audio title set program information table (ATS_PGCIT),an audio title set cell playback information table (ATS_C_PBIT), and anaudio title set audio still video playback information table(ATS_ASV_PBIT).

ATS_PGCIT includes one or more pieces of audio title set programinformation (ATS_PGI#1 to ATS_PGI#k), and ATS_C_PBIT includes the samenumber of pieces of audio title set cell playback information(ATS_C_PBI#1 to ATS_C_PBI#k) as the number of pieces of informationATS_PGI.

On the other hand, ATS_ASV_PBIT includes ATS program audio still videoplayback information search pointers (ATS_PG_ASV_PBI_SRP#1 toATS_PG_ASV_PBI_SRP#m), and ATS audio still video playback information(ATS_ASV_PBI#1 to ATS_ASV_PBI#n; n≦m≦99).

FIG. 27 shows the contents of audio title set program informationATS_PGI shown in FIG. 26.

This ATS_PGI includes the contents (ATS_PG_CNT) of an audio title setprogram, an ATS_PG entry cell number (ATS_PG_EN_CN), the startpresentation time (FAC_ST_PTM) of the first audio cell in ATS_PG, theplayback time (ATS_PG_PB_TM) of ATS_PG, and the pause time(ATS_PG_PA_TM) of ATS_PG.

ATS_PG_CNT includes: an entry representing the relationship between theprevious and current programs; an entry representing the relationshipbetween the playback time stamps of the previous and current programs;an entry (ATRN) representing the attribute of AOB or that of an audiostream in VOB; and an entry (DM_COEFTN) indicating a coefficient tablenumber to mix down AOB in ATS_PG (AOB_PG) having the number ofAOTT_AOB_ATR or AOTT_VOB_ATR defined in ATSI_MAT using the number ofATS_DM_COEFT defined in ATSI_MAT.

ATS_PG_EN_CN includes an entry of the number (1 to 255) of the first ATScell that forms ATS_PG.

FAC_ST_PTM includes an entry of lower 32 bits of the playback time stamp(or presentation time stamp PTS) described in the first audio packet inthe first audio cell in ATS_PG.

ATS_PG_PB_TM describes the total playback time of cells in ATS_PG. Thetotal playback time (seconds) assumes a value obtained by dividingATS_PG_PB_TM (32-bit data) by 90,000.

ATS_PG_PA_TM describes the pause time that can be defined at thebeginning of ATS_PG. This pause time (seconds) assumes a value obtainedby dividing ATS_PG_PA_TM (32-bit data) by 90,000.

FIG. 28 shows the contents of audio title set cell playback informationATS_C_PBI shown in FIG. 26.

This ATS_C_PBI includes an index number (ATS_C_IXN) of a cell (ATS_C) inan audio title set, the type (ATS_C_TY) of ATS_C, the start address(ATS_C_SA) of ATS_C, and the end address (ATS_C_EA) of ATS_C.

In ATS_C_IXN, “01h” is written when ATT has no AOBS.

When ATT has AOBS, the contents of ATS_C_IXN change as follows inaccordance with the contents of ATS_C.

-   -   *When ATS_C is the silent cell or picture cell described above,        “00h” is written in ATS_C_IXN as the index number of this ATS_C;        and    -   *when ATS_C is the above-mentioned audio cell, one of “1” to        “99” is written in ATS_C_IXN as the index number of this ATS_C.

The index number of the first audio cell (having ATS_C with the smallestnumber except for picture and silent cells) in ATS_PG is set at “1”.Similar index numbers may be appropriately assigned to one or more cellsATS_C in ATS_PG.

In all bits of ATS_C_TY, “0” is written when ATT has no AOBS.

On the other hand, when ATT has AOBS, the composition (ATS_C_COMP) ofATS_C and its usage (ATS_C_Usage) are written in ATS_C_TY.

More specifically, when the cell of interest is an audio cell consistingof only audio data, “00b” is written in ATS_C_COMP (2 bits);

when the cell of interest is an audio cell consisting of audio data andreal time information, “01b” is written in ATS_C_COMP (2 bits);

when the cell of interest is a silent cell consisting of only audiodata, “10b” is written in ATS_C_COMP (2 bits); and

when the cell of interest is a picture cell consisting of only stillpicture data, “11b” is written in ATS_C_COMP (2 bits).

On the other hand, ATS_C_Usage is written with data (0001b) indicatingthe usage as a “spotlight part” for highlighting (spotlighting) thecurrently displayed specific part of audio manager menu AMGM.

When ATS has AOTT_AOBS, ATS_C_SA describes the start address of ATS_Cexpressed by the relative logical block number from the first logicalblocks of AOTT_AOBS which records that ATS_C.

On the other hand, when ATS has no AOTT_AOBS, ATS_C_SA describes thestart address of ATS_C expressed by the relative logical block numberfrom the first logical block in AOTT_VOBS which records that ATS_C.

When ATS has AOTT_AOBS, ATS_C_EA describes the end address of ATS_Cexpressed by the relative logical block number from the first logicalblocks of AOTT_AOBS which records that ATS_C.

On the other hand, when ATS has no AOTT_AOBS, ATS_C_EA describes the endaddress of ATS_C expressed by the relative logical block number from thefirst logical block in AOTT_VOBS which records that ATS_C.

FIG. 29 is a block diagram showing an example of an apparatus forplaying back information recorded on the audio zone shown in FIG. 3 orthe video zone shown in FIG. 4 from the optical disc (DVD audio disc)shown in FIG. 1. This playback apparatus has an arrangement of a DVDvideo DVD audio compatible player that can play back not only audio databut also video data. (Although the detailed description of thearrangement will be omitted, this player may be compatible with existingCDs.)

The optical disc playback apparatus shown in FIG. 29 comprises remotecontroller 5 for accepting user's operations, remote controller receiver4A for receiving the operation state of remote controller 5, key inputportion 4 for accepting user's operations on the playback apparatus mainbody side, and panel display 4B which informs the user of his or heroperation result, the playback process of DVD audio disc 10, and thelike, and is arranged on the playback apparatus main body (and/or remotecontroller). As external devices in addition to these devices, monitor6, and loudspeakers 8L and 8R are prepared. (The illustratedloudspeakers are used for a 2-channel stereophonic system. However, uponmultichannel playback, a required number of loudspeaker systems andtheir drive amplifiers are prepared separately.)

Key input portion 4, panel display 4B, remote controller 5, and monitor6 make up a visual user interface. Monitor 6 is used not only as aplayback video monitor of a DVD audio disc with a still picture, butalso as a display means for, e.g., on-screen display OSD or the like.Monitor 6 is not limited to a direct-view type CRT display, liquidcrystal display, plasma display, or the like, but may comprise a videoprojector for projecting various video data (menu window, still pictureobtained by taking the recording site, and the like) including OSDinformation onto a large screen, in addition to the direct-view typedisplay.

User operation information input at remote controller 5 is supplied tomicrocomputer (MPU or CPU) 500 of system controller 50, which controlsthe operation of the overall playback apparatus, via remote controllerreceiver 4A. Controller 50 also includes ROM 502 which stores a controlprogram and the like executed by MPU 500.

User operation information input at key input portion 4 is directlysupplied to MPU 500. MPU 500 appropriately displays the operationconditions (various setup states and playback information of a DVD disc)of the playback apparatus corresponding to the user operationinformation on panel display 4B.

MPU 500 is connected to RAM 52 and memory interface (memory I/F) 53. TheI/O control of RAM 52 is made via memory I/F 53. MPU 500 uses RAM 52 asa work area, and controls the operations of disc drive 30, systemprocessor 54, video decoder 58, audio decoder 60, sub-picture decoder62, and DAC & reproduction processing block 64 on the basis of variousprocessing programs stored in ROM 502.

Disc drive 30 rotates disc 10 set on a tray (inside DISC•TRAY•INLET inFIG. 30) of the playback apparatus main body, and reads out from disc 10recorded data (in addition to audio data including voice/musicinformation, main picture data/video data containing moving pictureinformation/still picture information, sub-picture data containingsuperimposed dialog information/menu information, and the like if theyare recorded on disc 10). Readout data are subjected to signalprocessing such as signal demodulation, error correction, and the like,and are converted into a data sequence in the pack format (see FIGS. 6to 8). Then, the data sequence is sent to system processor 54.

System processor 54 has a packet transfer processor (not shown) whichdetermines the types of various packets contained in data played backfrom disc 10, and distributes data in these packets to the correspondingdecoders (58 to 62).

The packet transfer processor segments the data sequence in the packformat from the disc drive 30 in units of types of packs (navigationpack, video pack, sub-picture pack, audio pack, real time informationpack, and still picture pack). Each segmented pack records transfer timedata and ID data indicating the type of data.

System processor 54 transfers the video pack, sub-picture pack, andaudio pack respectively to video decoder 58, sub-picture decoder 62, andaudio decoder 60 with reference to the transfer time data and ID data ofthese packs. Note that the still picture pack is transferred to videodecoder 58. The audio pack corresponding to silent cells or real timeinformation pack is transferred to audio decoder 60.

Also, system processor 54 transfers control data in the navigation packto RAM 52 via memory I/F 53. MPU 500 controls playback operations of theindividual units of the playback apparatus main body with reference tothe transferred control data in the RAM.

Video decoder 58 generates video data before compression by decodingMPEG-encoded video data in the video pack transferred from systemprocessor 54.

Sub-picture decoder 62 generates bitmap sub-picture data beforecompression by decoding runlength-compressed sub-picture data in thesub-picture pack transferred from system processor 54.

This sub-picture decoder 62 has a highlight processor (not shown) forhighlighting (in case of DVD video) or spotlighting (in case of DVDaudio) decoded sub-picture data in addition to a sub-picture decoder fordecoding sub-picture data from system processor 54.

The sub-picture decoder obtains an original bitmap picture by expandingpixel data (including emphasized pixels, pattern pixels, backgroundpixels, and the like) in units of a predetermined number of bits (2bits), which have been runlength-compressed according to a predeterminedrule.

The highlight processor (not shown) executes corresponding highlightprocessing (spotlight processing) in accordance with highlightinformation or spotlight information (e.g., the X- and Y-coordinatevalues which define a rectangular region where a menu selection item isdisplayed, color code, and highlight color (spotlight color)/contrastvalue) supplied from MPU 500.

The highlight processing can be used as a means for helping the usereasily recognize a specific displayed item (a button for selecting aspecific item such as the type of playback spoken language, the type oflanguage used for the playback superimposed dialog, and the like; or abutton for selecting a specific item such as the sampling frequency, thenumber of quantization bits, the number of playback channels, and thelike of playback sound) on the visual user interface on monitor 6.

Incidentally, one spotlight part is defined as a cell. The spotlight isused to specify specially selected part by the content provider. A DVDaudio player may selectively present the spotlight parts as an optionalfunction.

When the color and contrast of the decoded sub-picture data in units ofpixels have been changed in correspondence with the highlightinformation (spotlight information), the changed sub-picture data issupplied to a picture synthesizer (not shown) in video processor 640.The picture synthesizer synthesizes the decoded picture data and thesub-picture data after the highlight processing (spotlight processing),and the synthesized picture is displayed on monitor 6.

RAM 52 mentioned above includes a menu table for storing the startaddresses of a sub-picture menu, audio menu, angle menu, chapter(program) menu, and the like. To emphasize a specific portion of thesemenus, the highlight processing (spotlight processing) may be used.

Audio decoder 60 generates monaural, 2-channel stereophonic, ormultichannel stereophonic audio data by decoding audio data in the audiopack transferred from system processor 54. When audio data in the audiopack is compression-encoded data (MPEG, AC-3, or the like), that data isdecoded inside audio decoder 60.

Video data (normally, moving picture signal) decoded by video decoder58, and sub-picture data (normally, superimposed dialog or menu bitmapdata) decoded by sub-picture decoder 62 are transferred to videoprocessor 640. In this video processor 640, the video data andsub-picture data are mixed at a predetermined ratio to obtain a finalanalog video signal (composite video signal, separate S signal, orcomponent signals Y/Cr/Cb). Then, the analog video signal is output tomonitor 6.

When the video data decoded by video decoder 58 corresponds to main partof a movie on DVD video disc 10, the sub-picture data normallycorresponds to a superimposed dialog in the language selected by theuser. Hence, the movie with the superimposed dialog is played back onmonitor 6.

When the video data decoded by video decoder 58 corresponds to menu partof the movie, the sub-picture data normally corresponds to charactersthat make up the menu and user selection buttons (appropriatelyhighlighted). In such case, a menu background (still picture or movingpicture) is displayed on monitor 6 on the basis of the video data, andbuttons, the display states of which change in correspondence withuser's selection operations, are superimposed on the background pictureon the basis of the sub-picture data.

On the other hand, when the video data decoded by video decoder 58corresponds to a still picture of DVD audio disc 10, the sub-picturedata corresponds to, e.g., comment text in the language selected by theuser. In such case, a still picture with text is displayed on monitor 6.

Note that video processor 640 includes an OSD unit for generatingon-screen display (OSD) data. User's operation at, e.g., remotecontroller 5 is processed by MPU 500, and the processing result is sentfrom MPU 500 to the OSD unit of video processor 640. The OSD unitgenerates picture data corresponding to the processing result from MPU500, and outputs it in the analog video signal format to monitor 6.

In other words, video processor 640 converts and multiplexes digitalsignals output from video decoder 58 and sub-picture decoder 62 into ananalog signal.

Frame memory 642 is connected to video processor 640. Frame memory 642is used for multiplexing pictures of the video and sub-picture data, andis also used for n-split (e.g., 4-split) multiscreen display.

Frame memory 642 can be used when video data from video decoder 58 isfrozen as a still picture in case of, e.g., a chapter search, and thestill picture is sent to monitor 6 before the target chapter begins tobe played back.

Furthermore, frame memory 642 can also be used when an OSD displaycorresponding to the user's operation result is multiplexed on videodata.

Audio data decoded by audio decoder 60 is transferred to DAC & outputcircuit 644. DAC & output circuit 644 converts the audio data (digital)from audio decoder 60 into an analog audio signal, appropriatelyamplifies the signal, and then sends that signal to loudspeakers BL and8R.

When multichannel audio data are mixed down to 2-channel audio data onthe basis of the entry of ATS_DM_COEFT in audio title set informationmanagement table ATSI_MAT (cf. explanation of FIG. 25), the mix-downcoefficient (parameter) is sent from MPU 500 to DAC & output circuit644. Then, DAC & output circuit 644 mixes down multichannel audio datadecoded by audio decoder 60 to 2-channel data on the basis of thereceived coefficient, and outputs 2-channel analog audio signals.

Video processor 640, frame memory 642, and DAC & output circuit 644 makeup the DAC & reproduction processing block.

Note that system processor 54, video decoder 58, audio decoder 60, andsub-picture decoder 62 respectively include system time clock (STC) foroperation timings and a register for temporarily storing commands,information, and the like sent from system MPU 500.

FIG. 30 shows an example of the front panel of the playback apparatusshown in FIG. 29. This front panel has fluorescent display (FL display)4B corresponding to panel display 4B shown in FIG. 29.

FL display 4B shown in FIG. 30 displays an album name and/or group nameas characters in accordance with audio text data manager ATXTDT_MG inAMGI. In the example shown in FIG. 9, “Vol. 1 of works of Beethoven” isdisplayed as the album name, and “Symphony No. 1” is displayed as thegroup name.

Also, a numeric indicator on the left side of FL display 4B displays atitle number (in case of DVD video) or group number (in case of DVDaudio), track number, and index number.

When optical disc 10 set on the disc tray shown in FIG. 30 is an AV disc(a disc having ATT_SRP shown in FIG. 20), a character indicator on theright side near the center of FL display 4B highlights “AV disc”, asshown in FIG. 30. When the set disc is an A disc (a disc having AOTT_SRPshown in FIG. 22), “A disc” is highlighted on the character indicator onthe right side of FL display 4B. When the set disc is a video disc whichhas no ATS but consists of only VTS (a disc having no ATS directoryshown in FIG. 12), “video disc” is highlighted on the characterindicator on the right side of FL display 4B.

Furthermore, a numeric indicator on the right side of FL display 4Bindicates the sampling frequency and the number of quantization bits ofthe audio contents to be played back. These indications can beautomatically made on the basis of the contents of AOTT_AOB_ATR orAOTT_VOB_ATR in audio title set information management table ATSI_MAT.

A DVD audio player that plays back DVD audio disc (A disc or AV disc) 10may include the following two types of players:

<C1> a player that can play back both picture and audio data complyingwith the audio format, i.e., a player that processes both AOTT and AVTT;and

<C2> a player that can play back only audio data complying with theaudio format, i.e., a player that processes only AOTT.

The player of type <C1> suffices to load only search information (FIG.20) described in ATT_SRPT to playback contents.

On the other hand, the player of type <C2> suffices to load only searchinformation (FIG. 22) described in AOTT_SRPT to playback contents.

In this manner, the playback methods of the respective types of playerscan be facilitated. Of course, the player of type <C2> cannot play. backATT#1 and ATT#9 in FIG. 23 since they do not include any AOTT.

The above-mentioned DVD audio player shown in FIG. 29 corresponds tothat of type <C1>. The operation of this player will be explained belowtaking playback of disc 10 with the data structure shown in FIG. 14 asan example.

When disc 10 with the data structure shown in FIG. 14 is to be playedback by a normal DVD video player, this video player loads VMG in theVTS directory under the root directory shown in FIG. 12, and determinesa title to be played back on the basis of the loaded information. Theplayer plays back all or some objects in object set VOBS#1 or VOBS#2 inFIG. 14 in accordance with an instruction of a playback unit defined inVTS corresponding to the determined title.

In the data structure shown in FIG. 14, the video player recognizesareas other than VMG, VTS#1, and VTS#2 as other recording area 73 (FIGS.3 and 4). For this reason, the video player can normally play backVOBS#1 and VOBS#2 independently of data recorded in the areas recognizedas other recording area 73. In this case, objects present in otherrecording area 73 cannot be played back by the video player.

On the other hand, disc 10 with the data structure shown in FIG. 14 isto be played back by the DVD audio player shown in FIG. 29, this audioplayer loads AMG in the ATS directory under the root directory shown inFIG. 12, and plays back contents on the basis of the loaded information.Upon title designation by AMG, a playback unit defined in VTS recordedin DVD video zone 72 (FIG. 4) can be designated as well as a playbackunit defined in ATS recorded in DVD audio zone 71 (FIG. 3).

The playback unit defined in ATS designates not only the playback routeof objects (AOBS#1 or AOBS#2) recorded in DVD audio zone 71 but alsodesignates that of audio data recorded in objects (e.g., VOBS#1) in DVDvideo zone 72.

VOBS#1 indicated by hatching in FIG. 14 exemplifies DVD video partshared from the DVD audio side. Note that arrow (a) indicates a casewherein the playback unit in video zone 72 is referred to, and arrow (b)indicates a case wherein audio part of objects (VOBS#1) in video zone 72is referred to by the playback unit in audio zone 71.

When audio part of objects (VOBS#1) in video zone 72 is referred to bythe playback unit in audio zone 71, the shared reference part (shared byDVD audio and DVD video) can have a definition different from that ofindividual units (cell, program, program chain) defined by definitioninformation (VTSI) of the playback unit in video zone 72. That is, thevideo player and audio player may have different playback methods foreven an identical object (see FIG. 5).

Note that the shared part is used in units of video object units VOBU.This is because audio data streams and other (video and sub-picture)data streams are packed and time-division multiplexed in units of VOBUs.

As shown in FIG. 14, since audio zone 71 is physically located in frontof video zone 72, the addresses of playback units designated from theirmanagement information can be limited to those in the positivedirection. In this way, design and development of an audio player can besimplified.

Note that the operation of the video player using the data structureshown in FIG. 16 is the same as that in FIG. 14 mentioned above.

The operation of the audio player using the data structure shown in FIG.16 is nearly the same as that in FIG. 14. The audio player jumps to thebeginning of AMG to load management information, and plays back objectsets AOBS#1 and AOBS#2. Although AOBS#1 is an object in the DVD videozone, ATSI#1 re-defines cells, programs, and a program chain of AOBS#1.Note that AOBS#1 is also used in units of VOBUs.

The embodiment described above has exemplified a case wherein DVD audiodata and/or DVD video data contained in volume space 28 are recorded onoptical disc 10. However, the data structure (FIGS. 3 to 28) of thepresent invention is not limited to data recorded on optical disc 10.For example, bit streams containing data with the structure shown inFIGS. 3 and 12 may be received via digital broadcast or digitallycommunication. (In such case, a radio wave or communication line servesas a medium. Also, a DVD broadcast receiver or a communication terminalsuch as a personal computer serves as a DVD audio player.)

FIG. 31 is a plan view of double-layered optical disc OD used as anotherexample of a two-substrate-joined information recording medium of thepresent invention, when viewed from the read laser receiving face side.This optical disc OD has an outer diameter of 120 mm, center hole 70defining its inner diameter of 15 mm, and a thickness of 1.2 mm, and isprepared by joining two 0.6-mm thick polycarbonate substrates. Each ofthe joined substrates is formed with a doughnut-like informationrecording layer (FIG. 31 illustrates only layer 10 of one substrate).The inner diameter of this doughnut-like information recording layer isapproximately 45 mm, and its outer diameter is around 117 mm in maximum.Polymer film spacer 60 (an inner diameter of 15 to 16 mm, an outerdiameter of 20 to 21 mm, and a thickness around 40 μm to 70 μm (e.g., 50μm)) is placed coaxial with center hole 70 of optical disc OD with theaforementioned structure, while being sandwiched between the twosubstrates.

As a polymer film used for spacer 60, a polycarbonate film, polyethyleneterephthalate film, polyimide film, and the like can be used unlessotherwise specified. When label information is printed there, apolycarbonate film is suitable. In this case, upon printing a label, thepractical thickness after printing is controlled to a desired thickness(e.g., 50 μm)

Note that spacer 60 may be omitted as long as the spacing between joinedsubstrates 30 and 40 can be managed to fall within the range between 40μm to 70 μm.

FIG. 32 is a partially enlarged schematic sectional view ofdouble-layered optical disc OD shown in FIG. 31. As shown in FIG. 32,this disc OD is comprised of polycarbonate substrate 30 for holding afirst information recording layer, gold thin film (first recordinglayer; a thickness of 11 to 14 nm, e.g., around 13 nm) 10 on which firstinformation is recorded, adhesive layer 50 which is transparent withrespect to laser beam RL, aluminum-molybdenum alloy thin film (secondinformation recording layer; a thickness of 40 nm or more, e.g., around100 nm) 20, and polycarbonate substrate 40 for holding the secondinformation recording layer, when viewed from the receiving face of readlaser beam RL. On the surface of substrate 40 opposite to the read laserRL receiving face of substrate 30, label LB that prints information(visual pattern information such as characters, graphics, patterns, andthe like) pertaining to recorded information (the first information andsecond information) is adhered, as needed.

Film spacer 60 coaxially sandwiched between substrates 30 and 40 at theposition of center hole 70 has a thickness of 50 μm, and adhesive layer50 sandwiched between substrates 30 and 40 at the same level as spacer60 has a constant thickness (around 55±15 μm) nearly the same as thefilm thickness (50 μm) of spacer 60. If the thickness of adhesive layer50 need be increased, the film thickness of spacer 60 can be increasedaccordingly.

By selecting the film thickness of gold thin film 10 that forms thefirst information recording layer to fall within the range from 11 nm to14 nm (preferably, around 13 nm), read laser reflected light beamshaving nearly the same intensities can be obtained from both first andsecond information recording layers 10 and 20.

Note that first information recording layer 10 may be formed of anothermaterial (gold alloy, copper, silver, brass, copper-zinc alloy,copper-aluminum alloy, or the like) that exhibits a laser reflectanceand laser transmittance equivalent to those of the gold thin film withrespect to read laser beam having a wavelength of 650 nm (or 635 nm).

By selecting the film thickness of the aluminum-molybdenum alloy thinfilm 20 that forms the second information recording layer to be 40 nm ormore, the laser reflectance of film 20 can be set at a practicallysufficient value (reflectance of 80% or more). In this embodiment, thefilm thickness setup value of second information recording layer 20 isselected to be around 100 nm.

Second information recording layer 20 can be formed of aluminum alone.However, using an alloy of aluminum and a high-melting point metal suchas molybdenum, tantalum, cobalt, chromium, titanium, platinum, or thelike, aging (environmental reliability) of the reflectance of thin film20 for the second information recording layer can be greatly reduced.

Molybdenum has a function of improving the oxidation resistance ofsecond information recording layer 20, but its mixing ratio has a properrange, i.e., falls within the range from 1 to 20 at % in practice. Theratio of molybdenum in aluminum-molybdenum alloy thin film 20 preferablyfalls within the range from 1 to 20 at %. In this embodiment, the ratioof molybdenum is set at 20 at %. If this ratio is higher than 20 at %,the laser reflectance of second information recording layer 20 lowerseven when thin film 20 has a film thickness of 40 nm or more.

The wavelength of read laser beam RL may be 635 nm in addition to 650 nmmentioned above, or may be shorter. However, if a different wavelengthis used, the optimal film thickness of spacer 60 may change (the optimalfilm thickness may also change depending of the physical properties ofadhesive layer 50). It is practical to experimentally determine theoptimal film thickness using a plurality of samples after the laserwavelength, the material of adhesive layer 50, the materials ofsubstrates 30 and 40 used in practice are determined. This determinationis made so that the C/N (carrier to noise ratio) of the read signal fromeach of recording layers 10 and 20 has a desired value or more, and asufficiently high joint strength of substrates 30 and 40 is assured.

The following physical parameters of joined optical disc OD shown inFIGS. 31 and 32 may be used.

[Outer Diameter] 12-cm disc > 120.00 ± 0.30 mm  8-cm disc > 80.00 ± 0.30mm [Center Hole 70] 12-cm/8-cm (common) > 15.00 + 0.15 mm, −0.00 mm[Joined Thickness] 12-cm/8-cm (common) > 1.20 + 0.30 mm, −0.06 mm [InnerDiameter of Disc Clamp Area] 12-cm/8-cm (common) > 22.0 mm (maximum)[Outer Diameter of Disc Clamp Area] 12-cm/8-cm (common) > 33.0 mm(minimum) [Thickness of Disc Clamp Area] 12-cm/8-cm (common) > 1.20 +0.20 mm, −0.10 mm [Joined Disc Weight] 12-cm disc > 13 g to 20 g  8-cmdisc > 6 g to 9 g [Moment of Inertia of Joined Disc] 12-cm disc > 0.040g · m² (maximum)  8-cm disc > 0.010 g · m² (maximum) [Dynamic Balance ofJoined Disc] 12-cm disc > 0.010 g · m (maximum)  8-cm disc > 0.0045 g ·m (maximum)

FIG. 33 schematically shows a partial section of a modification of theone-side read type two-substrate-joined double-layered disc shown inFIG. 32, i.e., joined optical disc OD having a single informationrecording layer.

In the modification shown in FIG. 33, information recording layer 20shown in FIG. 32 is replaced by dummy layer 20 d on which no informationis recorded. When information recording layer 10 can store the totalvolume of data to be stored in disc OD, the modification shown in FIG.33 can be used. Dummy layer 20 d can be formed of an aluminum-basedmetal thin film painted with a given information pattern having nopractical contents. (Note that “painted with a given information patternhaving no practical contents” includes not only a case wherein nothingis really recorded, but also a case wherein simple data such as “0”s or“1”s are fully recorded on the entire recording face.)

FIG. 34 shows a modification of the structure shown in FIG. 33, andschematically illustrates a partial section of two-substrate-joinedoptical disc OD having a single information recording layer.

In the modification shown in FIG. 34, information recording layer 20shown in FIG. 32 is replaced by dummy & label layer 20 db having a labelpattern. If this optical disc OD is found to be a joined single-layereddisc by initially reading some information on information recordinglayer 10, the playback apparatus of this disc OD can be initialized notto access information on dummy & label layer 20 db. In such case, sincedummy & label layer 20 db need not reflect read laser beam RL, thematerial of dummy & label layer 20 db can be selected from variousmaterials. For example, a polycarbonate film printed with a labelpattern may be used as dummy & label layer 20 db.

In the modifications shown in FIGS. 33 and 34, the thickness of dummylayer 20 d or 20 db need not be especially controlled. However, thethickness of substrate 40 including that of dummy layer 20 d or 20 db iscontrolled to a predetermined value (0.6 mm).

Using transparency of polycarbonate substrates 30 and 40, characters,patterns, and the like associated with information recorded on the discmay be printed on spacer 60 sandwiched between substrates 30 and 40. Inthis way, the spacer 60 portion at the center of the disc can be used asa disc label although its visual information entry amount is small.

In the aforementioned embodiment, an aluminum-molybdenum alloy thin filmis used as second information recording layer 20. However, the presentinvention is not limited to such specific film. Depending on theembodiment or modification of the present invention, a pure aluminumlayer, gold layer, an alloy layer of aluminum and a high-melting pointmetal (tungsten, tantalum, nickel, cobalt, platinum, chromium, titanium,or the like) other than molybdenum, which has a high melting point, highstrength, and high oxidation resistance, and the like may be used inpractice. However, the material of first information recording layer 10is limited to that (gold alloy, copper, silver, brass, copper-zincalloy, copper-aluminum alloy, or the like) that exhibits a laserreflectance and laser transmittance equivalent to those of gold withrespect to a laser beam with a specific wavelength used, when theselected material forms a thin film.

In the above description, ultraviolet setting resin layer (adhesivelayer) 50 has a thickness of 50 μm. However, when joined disc OD shownin FIG. 31 is a read-only DVD audio disc (DVD-ROM), this thickness ispreferably selected from the range from 40 μm to 70 μm. When joined discOD shown in FIG. 31 is a read/write DVD audio disc (DVD-RAM or DVD-RW),the thickness of adhesive layer 50 is often preferably smaller than thatof a read-only disc. In such case, the thickness of adhesive layer 50can be selected from the range from 20 μm to 40 μm.

As an outer size of optical disc OD, 5″ type (diameter of 120 mm) and3.5″ type (diameter of 80 mm) have been exemplified. The presentinvention can also be applied to joined optical discs having other sizessuch as 2.5″ type (diameter of 63 min) and the like. In this case, theoptimal adhesive layer thickness (or the thickness of spacer 60) can bedetermined in correspondence with the disc size, disc material, discpurpose (ROM or RAM), the type of adhesive, and other conditions.

In the above description, a film ring similar to a disc has beenexemplified as spacer 60. However, the shape of spacer 60 is not limitedto the ring shape. The inner hole of spacer 60 may have an arbitrarypolygonal shape. Similarly, the outer shape of spacer 60 may have anarbitrary polygonal shape as long as the diameter of its circumscribedcircle does not enter the region of the information recording layershown in FIG. 31. For example, a polygonal film (e.g., a thickness of 50μm) which has a hexagonal outer shape that is circumscribed by a circlehaving a diameter of 33 mm, and an octagonal inner shape that inscribesa circle having a diameter of 15 mm may be used as spacer 60. When discrecorded information (characters, symbols, or graphics) is printed onspacer 60, spacer 60 is preferably not limited to a circular ring toimprove its value (mainly in terms of its design).

FIG. 35 is a graph showing changes in allowable range of the thickness(ordinate) of a substrate (30 or 40) to be joined as a function of therefractive index (abscissa) of the substrate material when coherentlight having a wavelength of 650 nm is used and a pair of substrates(30, 40) each having a single substrate/single recording layer structureshown in FIG. 32 is used.

In this graph, if the refractive index of the substrate is 1.45, thesubstrate thickness is controlled to fall within the range from theupper limit of 0.643 (point P01) to the lower limit of 0.583 (point P03)(the central value is 0.615 mm at point P02). For example, if therefractive index of a polycarbonate substrate is 1.56, the substratethickness is controlled to fall within the range from the upper limit of0.630 (point P11) to the lower limit of 0.570 (point P13) (the centralvalue is 0.600 mm at point P12). If the refractive index of thesubstrate is 1.65, the substrate thickness is controlled to fall withinthe range from the upper limit of 0.630 (point P21) to the lower limitof 0.570 (point P23) (the central value is 0.600 mm at point P22).

In the embodiment of the present invention, a transparent substrate (30,40) made of polycarbonate or the like, the thickness of which fallswithin the range bounded by points P01 to P23 in this graph is used.

FIG. 36 is a graph showing changes in allowable range of the thickness(ordinate) of a substrate to be joined as a function of the refractiveindex (abscissa) of the substrate material when coherent light having awavelength of 650 nm is used and a pair of substrates each having asingle substrate/dual recording layer structure shown in FIG. 32 areused.

In this graph, if the refractive index of the substrate is 1.45, thesubstrate thickness is controlled to fall within the range from theupper limit of 0.653 (point Q01) to the lower limit of 0.563 (pointQ03). If the refractive index of the substrate is 1.56, the substratethickness is controlled to fall within the range from the upper limit of0.640 (point Q11) to the lower limit of 0.550 (point Q13) (the centralvalue is approximately 0.595 mm). If the refractive index of thesubstrate is 1.65, the substrate thickness is controlled to fall withinthe range from the upper limit of 0.640 (point Q21) to the lower limitof 0.550 (point Q23).

In the embodiment of the present invention, a transparent substrate (30,40) made of polycarbonate or the like, the thickness of which fallswithin the range bounded by points Q01 to Q23 in this graph is used.

Incidentally, the term “video” used in this specification refers to a“movie” picture. No video (“movie” picture) can be added to an audioonly title AOTT, while a “still” picture can be added to the AOTT. Thus,an audio title set directory AUDIO_TS may contain still picture data butmay not contain video data.

According to the present invention, the data structure of the DVD audioformat can be realized in a form similar to that of the video formatwithout modifying the DVD video format that has already been put intoapplications. In this case, an audio volume can exist in a single volumespace to share objects of a video volume. A DVD disc (A disc or AV disc)formed with this data structure can play back appropriate objects inboth the video player and audio player.

Since the data structure of the present invention is characterized bysharing some objects of DVD video without conflicting existing DVDvideo, DVD video and DVD audio can expand the infrastructure incooperation with each other. This also brings about secondary merits,i.e., a reduction of the manufacturing cost of playback apparatuses,media, and other associated products.

1. A digital information recording medium embodied as an optical discfor use with an optical disc drive, wherein said optical disc has anoutline of two-adhesive substrates, and includes a center hole, a clamparea around the center hole, and a read-out face around the clamp area,said read-out face is located at one of the two-adhesive substrates, theoptical disc includes a spiral track on which sectors are placed, anddata can be reproduced from the sectors using a laser, said dataincluding audio contents and audio management information, the digitalinformation recording medium comprising: an audio data area storing theaudio contents; an audio management block storing the audio managementinformation; and wherein said audio contents includes audio data andaudio title set information including audio title set informationmanagement information, wherein said audio title set informationmanagement information includes one or more pieces of coefficientinformation describing one or more coefficients to mix down the audiodata having multi-channel outputs to 2-channel outputs, said audio titleset information contains at least one program information includinginformation which describes a coefficient table number of the at leastone piece of the coefficient information, and cell playback informationincluding index information which describes an index number of a cell ofthe audio contents, and wherein said index number describes 01 h ofhexadecimal notation when the audio content has no audio objects, saidindex number describes 00 h when the cell is a silent cell, and saidindex number describes a number from 1 to 99 when the cell is an audiocell.
 2. A medium according to claim 1, wherein said audio managementinformation includes a search pointer table, and wherein said searchpointer table includes a first search pointer including addressinformation of the audio contents, and a second search pointer includingaddress information of the video contents.
 3. A medium according toclaim 1, wherein said audio management block storing said audiomanagement information has physically or logically smaller addressesthan addresses of said video management block.
 4. A medium according toclaim 1, wherein said audio contents includes audio title setinformation, wherein said audio title set information includes audiotitle set program chain information for controlling the audio contents,wherein said audio title set program chain information includes an audiostill video playback information table, and wherein said audio stillvideo playback information table includes audio still video playbacksearch pointers and audio still video playback information.
 5. A mediumaccording to claim 1, wherein contents of said audio data area arerecorded in audio packs configured to store data of the audio contents,and still picture packs configured to store data of a still picture tobe played back during playback of the contents of said audio packs.
 6. Amedium according to claim 1, wherein said audio title set informationmanagement information includes attribute information indicating apredetermined sampling frequency and a predetermined number ofquantization bits used in the audio data.
 7. An apparatus for playingback the audio or video contents from the medium as defined in claim 1,said apparatus comprising: a drive unit configured to read informationof the audio management block and to playback contents of the audio dataarea.
 8. The medium of claim 1, wherein a refractive index of said oneof the two-adhesive substrates is selected from a range from 1.45 to1.65, and a thickness of said one of the two-adhesive substrates isselected from a range from 0.550 mm to 0.653 mm.
 9. A method ofreproducing data from an optical disc using an optical disc drive, saiddata including audio contents and audio management information, whereinsaid disc includes, an audio data area storing the audio contents; anaudio management block storing the audio management information; andwherein said audio contents includes audio data and audio title setinformation including audio title set information managementinformation, wherein said audio title set information managementinformation includes one or more pieces of coefficient informationdescribing one or more coefficients to mix down the audio data havingmulti-channel outputs to 2-channel outputs, said audio title setinformation contains at least one program information includinginformation which describes a coefficient table number of the at leastone piece of the coefficient information, and cell playback informationincluding index information which describes an index number of a cell ofthe audio contents, and wherein said index number describes 01 h ofhexadecimal notation when the audio content has no audio objects, saidindex number describes 00 h when the cell is a silent cell, and saidindex number describes a number from 1 to 99 when the cell is an audiocell, the reproducing method comprising: rotating the optical disc withthe optical disc drive; and reading the recorded data.